A car is moving along a straight horizontal road with a speed u 0 .If the coefficient of friction between the tires and the road is μ , the shortest distance in which the car can be stopped is
Block A of mass 2 kg is placed over a block B of mass 8 kg. The combination is placed on a rough horizontal surface. If g = l0 ms – 2 , coefficient of friction between B and floor = 0.5, , coefficient of friction between A and B = 0.4 and a horizontal force of 10 N is applied on 8 kg block, then the force of friction between A and B is
An eraser weighing 2N is pressed against the black board with a force of 5N. The coefficient of friction is 0.4. How much force parallel to the black board is required to slide the eraser upwards
Starting from rest, the time taken by a body sliding down on a rough inclined plane at 45° with the horizontal is, twice the time taken to travel on a smooth plane of same inclination and same distance. Then the coefficient of kinetic friction is
A block of mass m is kept on an inclined plane of a lift moving down with acceleration of 2 m s – 2 . What should be the coefficient of friction to let the block move down with constant velocity relative to lift?
The limiting friction between two surfaces a) depends on the nature of two surfaces b) is proportional to normal reaction c) is independent of apparent area of contact
A boy of mass M is applying a horizontal force P to slide a box of mass M’ on a rough horizontal surface. Coefficient of friction between the shoes of the boy and the floor is μ and that between the box and the floor is µ’ . In which of the following cases it is certainly not possible to slide the box?
If an external force and the frictional force acting on a body cancel each other and keep the body at rest, the frictional force is
A marble block of mass 2 kg lying on ice when given a velocity of 6 m s – 1 is stopped by friction in 10s. Then the coefficient of friction is (g = 10 m s – 2 )
A boy of mass 25kg slides down a rope hanging from the branch of a tree. If the force of friction against him is 50N, the boy’s acceleration is (g=10ms –2 )
A block of mass 2 kg rests on a rough inclined plane making an angle of 30 0 with the horizontal. If μ s = 0.6 , what is the frictional force on the block ?
In the figure, m A = 3kg and m B = 4 kg. For what minimum value of F, A starts slipping over B:(g=10ms –2 )
A 30 kg box has to move up an inclined slope of 30 0 to the horizontal at a uniform velocity of 5 m s – 1 . If the frictional force retarding the motion is 150N, the horizontal force required to move up is (g=10 m s – 2 )
A suitcase is gently dropped on a conveyor belt moving at 3 m/s. If the coefficient of friction between the belt and the suitcase is 0.5. Find the displacement of suitcase relative to conveyor belt before the slipping between the two is stopped (g = 10 m s – 2 )
A 40 kg slab rests on a frictionless floor. A l0 kg block rests on top of the slab. The static coefficient of friction between the block and the slab is 0.60 while the kinetic coefficient of friction is 0.40. The 10 kg block is acted upon by a horizontal force of 100 N. The resulting acceleration of the slab will be
In the arrangement shown in the figure mass of the block B and A are 2 m,,8 m respectively. Surface between B and floor is smooth. The block B is connected to block C by means of a pulley. If the whole system is released then the minimum value of mass of the block C so that the block A remains stationary with respect to B is: (Coefficient of friction between A and B is μ and pulley is ideal)
In figure coefficient of friction between m 1 and m 2 is μ and that between m 1 and the wall is zero. A force F is pressing the system against the wall. Minimum value of force required to hold the system in equilibrium is:
A block of mass M slides down a rough inclined surface of inclination ‘ θ ‘ and reaches the bottom at speed ’v’. However, if it slides down a smooth inclined surface of same length and same inclination, it reaches the bottom with speed kv. Coefficient of friction between the block and the rough incline is:
On the horizontal surface of a truck a block of mass 1 kg is placed ( μ = 0.6) and truck is moving with acceleration 5 m/s 2 , then the fictional force on block will be :
A man of mass 60 kg sitting on ice pushes a block of mass of 12 kg on ice horizontally with a speed of 5 ms -1 .The coefficient of friction between the man and ice and between block and ice is 0.2. If g =10 ms -2 ,the distance between man and the block, when they come to rest is
The minimum force required to start pushing a body up a rough (frictional coefficient μ ) inclined plane is F 1 while the minimum force needed to prevent it from sliding down is F 2 . If the inclined plane makes an angle θ with the horizontal such that tan θ = 2 μ , then the ratio F 1 F 2 is
A horizontal force of 100 N is applied a block of mass 10 kg is placed on a rough horizontal surface with a coefficient of kinetic friction, μ k = 0 .5 . Find the acceleration of the block. (Take g = 10 ms − 2 )
A horizontal force is applied on a body on a rough horizontal surface produces an acceleration ‘a’. If coefficient of friction between the body and surface which is μ is reduced to μ /3, the acceleration increases by 2 units. The value of ‘ μ ’ is
A body is sliding down a rough inclined plane. The coefficient of friction between the body and the plane is 0.5. The ratio of the net force required for the body to slide down and the normal reaction on the body is 1 : 2. Then the angle of the inclined plane is
A block of mass m is at rest on an inclined plane which is making angle θ with the horizontal. The coefficient of friction between the block and plane is μ . Then, frictional force acting between the surfaces is
An insect crawls up a hemispherical surface very slowly (see the figure). The coefficient of friction between the insect and the surface is 1/3. If the line joining the centre of the hemispherical surface to the insect makes an angle ex with the vertical, the maximum possible value of α is given by
Find the value of friction forces between the blocks A and B; and between B and ground. (Take, g=10 m s – 2 )
The rear side of a truck is open and a box of mass 20 kg is placed on the truck 4 m away from the open end ( μ = 015 and g = 10 m s – 2 ). The truck starts from rest with an acceleration of 2 m s – 2 on a straight road. The box will fall off the truck when it is at a distance from the starting point equal to
A block of mass M rests on a rough horizontal surface as shown. Coefficient of friction between the block and the surface is μ . A force F = Mg acting at angle θ with the vertical side of the block pulls it. In which of the following cases, the block can be pulled along the surface?
A block of mass m , lying on a rough horizontal plane, is acted upon by a horizontal force P and another force Q , inclined at an angle θ to the vertical upwards. The block will remain in equilibrium, if minimum coefficient of friction between it and the surface is
A uniform rope of length I lies on a table. If the coefficient of friction is μ , then the maximum length l 1 of the hanging part of the rope which can overhang from the edge of the table without sliding down is
Two blocks of masses m and 2m are placed one over the other as shown in figure. The coefficient of friction between m and 2m is μ and between 2m and ground is μ 3 . If a horizontal force F is applied on upper block and T is tension developed in string, then choose the incorrect alternative.
Directions: These questions consists of two statements each printed as Assertion and Reason. While answering these questions you are required to choose any one of the following four responses Assertion : A body of mass 10 kg is placed on a rough inclined surface ( μ = 0.7). The surface is inclined to horizontal at angle 30°. Acceleration of the body down the plane will be zero. Reason : Force of friction is zero.
An object is moving on a plane surface with uniform velocity 10 m s – 1 in presence of a force 10 N. The frictional force between the object and the surface is [DUMET 2011]
A given object takes n times as much time to slide down a 45° rough incline as it takes to slide down a perfectly smooth 45° incline. The coefficient of kinetic friction between the object and the incline is given by
sphere S of mass M is given a finite angular velocity about a horizontal axis through its centre. Now it is gently placed on a plank p of the same mass. The coefficient of friction between the two is μ and the plank rests on a smooth horizontal surface as shown in fig. (6). The initial acceleration of the sphere relative to the plank will be
An object is placed on the surface of a smooth inclined plane of inclination θ . It takes time t, to reach the bottom. If the same object is allowed to slide down a rough inclined plane of inclination q , it takes time n t to reach the bottom where n is a number greater than one. The coefficient of friction μ is given by
A block of mass 2 kg rests on a rough inclined plane making an angle of 30° with the horizontal. The coefficient of static friction between the block and the plane is 0.7. The frictional force on the block is
The acceleration of a body sliding down a rough inclined plane is given by (coefficient of kinetic friction between the plane and the body is μ )
Starting from rest, a body slides down a 45° inclined plane in twice the time it takes to slide the same distance in the absence of friction. What is the coefficient of friction between the body and the inclined plane ?
A block of mass M = 5 kg is resting on a rough horizontal surface for which the coefficient of friction is 0.2. When a force F = 40 N is applied, the acceleration of the block will be (g = 10 m s – 2 )
In the figure given, the system is in equilibrium. What is the maximum value that W can have if the friction force on the 40 N block cannot exceed 12.0 N
A plank having mass M is placed on smooth horizontal surface. Block of mass m is placed on it coefficient of friction between block and plank is μ 0 + kx 2 , where k is constant and x is relative displacement between block and plank. A force F is applied on block where F = at, where a = 10; t is in second. Find t 0 when relative motion will occur between block and plank
What is the maximum value of the force F such that the block shown in the arrangement, does not move
If the coefficient friction between A and B is μ , the maximum acceleration of the wedge A for which B will remain at rest with respect to the wedge is
Two blocks of mass 20 kg is connected as shown in the figure then friction force on the block exerted by horizontal surface is (system is released from rest) (g = 10 m / s 2 )
A rough vertical board has an acceleration a so that a 2 kg block pressing against it does not fall. The coefficient of friction between the block and the board should be
A block rest on a rough inclined plane making an angle 30 0 with the horizontal. The coefficient of static friction between the block and plane is 0.8. If the frictional force on the block is 10N, the mass of block is ( g = 10 m s – 2 )
A body of mass 500 g is taken up an inlclined plane of length 10 m and height 5 m, and then released to slide down to the bottom. The coefficient of friction between the body and the plane is 0.1. What is the amount of work done in the round trip ?
A block B of mass 2 kg is kept on the rough surface of a plank ‘P’ as shown in figure. If the plank starts moving to the right with acceleration 2 m / s 2 , acceleration of the block relative to the ground is 1 m / s 2 . Then coefficient of kinetic friction between the block and the plank is
A mass m= 0 .55 kg rests on a horizontal surface . The coefficient of static friction between the mass and the surface is 0 .4 , if the mass is pulled by a force F= 3 N as shown in the figure . The limiting friction between mass and the surface will be g = 10 m / s 2 .
A block of mass 2 kg is sliding down a rough inclined plane having inclination 30 0 with constant velocity of 0.5 m/s. Then coefficient of kinetic friction between the block and the same is
The limiting friction between two bodies in contact is independent of
A block of mass 1kg is kept on a rough inclined plane at θ = 30º with horizontal. The block is connected with a string as shown. Between the block and inclined plane µ s = 3 / 4 = tan37º .Then tension in the string is (g = 10ms –2 )
A body is just supported at the face of a cart moving at an acceleration a. The acceleration of the cart so that the body does not slide is
If man is walking, direction of friction is
When the angle of inclination of on inclined plane is θ , an object slides down with uniform velocity. If the same object is pushed up with an initial velocity u on the same inclined plane, it goes up the plane and stops at a certain distance on the plane. There after the body.
A wooden block of 100 kg is about to be pushed on a floor of coefficient of friction 0.4. What is the magnitude of the force of friction on the wooden block when it is just pushed ?
A block of weight 100N is lying on a rough horizontal surface. If coefficient of friction 1/√3 . The least possible force that can move the block is
A box is placed on the floor of a truck moving with an acceleration of 7 ms –2 . If the coefficient of kinetic friction between the box and surface of the truck is 0.5, find the acceleration of the box relative to the truck
A block of mass 4kg is placed in contact with the front vertical surface of a lorry. The coefficient of friction between the vertical surface and block is 0.8. The lorry is moving with an acceleration of 15 m/s 2 (g = 10ms -2 ). The force of friction between lorry and block is
Block A of mass m rests on the plank B of mass 3m which is free to slide on a frictionless horizo-ntal surface. The coefficient of friction between the block and plank is 0.2. If a horizontal force of magnitude 2 mg is applied to the plank B, the acceleration of A relative to the plank and relative to the ground respectively, are:
A 4 kg block A is placed at the top of 8 kg block B which rests on a smooth table. A just slips on B when a force of 20 N is applied on A. The maximum horizontal force F required to make both A & B move together is
Two blocks A and B are pressed against a vertical wall by applying a horizontal force 'F' as shown in the figure. There is no friction between A and B. Then a) Both the blocks A and B can be at rest for any magnitude of F b) B can be at rest A moves down for smaller magnitude of F c) Both A and B will move down for smaller magnitude d) A can be at rest and B moves down for larger magnitude of F
A uniform chain of length 2 m is lying on a horizontal table top with a length ‘x’ hanging over the edge of the table. If coefficient of static friction between the table top and the chain is 0.6, the maximum value of ‘x’ is
A plank with a box on it at one end is gradually raised about the other end. As the angle of inclination with the horizontal reaches 30 0 , the box starts to slip and slides 4.0 m down the plank in 4.0 s. The coefficients of static and kinetic friction between the box and the plank will be, respectively
A person wants to drive on the vertical surface of a large cylindrical wooden ‘well’ commonly known as ‘death well’ in a circus. The radius of the well is 2 meter, and the coefficient of friction between the tyres of the motorcycle and the wall of the well is 0.2, the minimum speed the motorcyclist must have in order to prevent slipping should be
A block of mass m, lying on a horizontal plane, is acted upon by a horizontal force P and another force Q, inclined at an angle θ to the vertical. The block ill remain in equilibrium, if the coefficient of friction between it and the surface is:
A block of mass m is placed in equilibrium on a moving plank. The maximum horizontal acceleration of the plank for μ = 0 . 2 is:
A lineman of mass 60 kg is holding a vertical pole. The coefficient of static friction between his hands and the pole is 0.5. If he is able to climb up the pole, what is the minimum force with which he should press the pole with his hands? (g = 10 m/s 2 )
If 100 N force is applied to 10kg block as shown in diagram, then acceleration produced for slab :
A heavy uniform chain lies on horizontal table top. If the coefficient of friction between the chain and the table surface is 0.5, the maximum percentage of the length of the chain that can hang over one edge of the table is
A body is sliding down an inclined plane forming an angle 30° with the horizontal. If the coefficient of friction is 0.3 then acceleration of the body is
A cube of weight 10N rests on a rough inclined plane of slope 3 in 5. The coefficient of friction is 0.6. The minimum force necessary to start the cube moving up the plane is
A block sliding down on a rough 45 0 inclined plane has half the velocity it would have been, the inclined plane is smooth. The coefficient of sliding friction between the block and the inclined plane is
The coefficient of friction between a hemispherical bowl and an insect is 0 .44 and the radius of the bowl is 0.6m. The maximum height to which an insect can crawl in the bowl will be
A 500 kg horse pulls a cart of mass 1500 kg along a level road with an acceleration of 1 m/s 2 . If coefficient of sliding friction is 0.2, then force exerted by the earth on horse is
An aeroplane requires for take off a speed of 108 kmph the run on the ground being 100m. Mass of the plane is 10 4 kg and the coefficient of friction between the plane and the ground is 0.2. Assuming the plane accelerates uniformly the minimum force required is (g =10ms -2 )
A man of mass 65 kg. is standing stationary with respect to a conveyor belt which is accelaccelerating with 1m / s 2 . If μ s is 0.2, the net force on the man and the maximum acceleration of the belt so that the man is stationary relative to the belt are (g =10m / s 2 )
A block slides down a rough inclined plane of slope angle θ with a constant velocity. It is then projected up the same plane with an initial velocity v. The distance travelled by the block up the plane before coming to rest is
The force required to move a body up a rough inclined plane is double the force required to prevent the body from sliding down the plane. The coefficient of friction when the angle of inclination of the plane is 60° is
A block weighing 10kg is at rest on a horizontal table. The coefficient of static friction between the block and the table is 0.5. If a force acts downward at 60º with the horizontal, how large can it be without causing the block to move? (g = 10ms –2 )
A block of mass m = 4kg is placed over a rough inclined plane having coefficient of friction μ = 0.6 as shown in fig. A force F = 10N is applied on the block at an angle 30 o . The contact force between the block and the plane is
A body is projected up a 45 0 rough incline. If the coefficient of friction is 0.5, then the retardation of the block is
A 4 kg block A is placed on the top of 8 kg block B which rests on a smooth table. A just slips on B when a force of 12 N is applied on A. Then, the maximum horizontal force F applied on B to make both A and B move together, is
Pushing force making an angle θ to the horizontal is applied on a block of weight w placed on a horizontal table. If the angle of friction is ϕ , the magnitude of force required to move the body is equal to
A block of mass 0.1 kg is held against a wall applying a horizontal force of 5 N on the block. If the coefficient of friction between the block and the wall is 0.5, the magnitude of the frictional force acting the block is
A block of mass m is placed on a wedge of mass 2 m which rests on a rough horizontal surface. There is no friction between the block and the wedge. The minimum coefficient of friction between the wedge and the ground, so that the wedge does not move, is
If the coefficient of friction between all surfaces is 0.4, then find the minimum force F to have equilibrium of the system. (Take, g = 10 ms -2 )
The upper half of an inclined plane of inclination θ is perfectly smooth while the lower half rough. A block starting from rest at the top of the plane will again come to rest at the bottom, if the coefficient of friction between the block and the lower half of the plane is given by
A 3 kg block is placed over a 10 kg block and both are placed on a smooth horizontal surface. The coefficient of friction between the blocks is 0.2. If a horizontal force of 20 N is applied to 3 kg block, accelerations of the two blocks (in ms -2 ) are (Take, g = 10 ms -2 ) [EAMCET 2013]
Pushing force making an angle 0 to the horizontal is applied on a block of weight W placed on a horizontal table. If the angle of friction is ϕ the magnitude of force required to move the body is equal to
Two masses A and B of 10 kg and 5 kg respectively are connected with a string passing over a frictionless pulley fixed at the corner of a table as shown in fig. The coefficient of friction of A with the table is 0.2 The minimum mass of C that may be placed on A to prevent it from moving is equal to
A log of weight W is pulled at a constant velocity and with a force F by means of a rope of length l. The distance between the free end of the rope and ground is h. Neglecting the thickness of the log, the coefficient of friction between log and ground is
A vehicle of mass m is moving on a rough horizontal road with momentum p, If the coefficient of friction between the tyres and the rod be μ , then stopping distance is
A block of mass 1 kg is at rest on a horizontal table. The coefficient of static friction between the block and the table is 0.50. If g = 10 m/s 2 , then the magnitude of a force acting upwards at an angle of 60° from the horizontal that will just start the block moving is
Two blocks of mass M and m are connected with a string which passes over a smooth pulley as shown in fig. The mass M is placed on a rough inclined plane. The coefficient of friction between the block and the inclined plane is µ. What should be the minimum mass m so that the block M slides upward ?
A block of mass 5 kg slides down a rough inclined surface. The angle of inclination is 45 0 . The coefficient of sliding friction is 0.20 . When the block slides 10 cm, the work done on the block by force of friction is
A body is moving down an inclined plane of slope 37 0 . The coefficient of friction between the body and plane varies as μ = O.3 x , where x is the distance travelled down the plane by the body. The body will have maximum speed (Take, g = 10 m s – 2 , sin37 0 = 3 5 )
A uniform rope of length / lies on a table. If the coefficient of friction is μ , then the maximum length x of the part of this rope which can overhang from the edge of the table without sliding down is
A block of wood weights 10 N and is resting on an inclined plank. The coefficient of friction is 0.7. The frictional forces that acts on the block when the plank is 30° inclined with the horizontal is
A heavy block of mass M is slowly placed on a conveyer belt moving with a speed v. The coefficient of friction between the block and the belt is µ. Through what distance will the block slide on the belt?
A block of mass M is placed on a rough horizontal surface. A force F = M g acts on the block. It is inclined to the vertical at an angle θ . The coefficient of friction is µ. The block can be pushed along the surface only when
A block of mass 2 kg is kept on the floor. The coefficient of static friction is 0.4 If a force F of 2.5 N is applied on the block as shown in fig. the frictional force between the block and the floor will be
A block of mass 2 kg is lying on an inclined plane, inclined to the horizontal at 30°. If the coefficient of friction between the block and the plane is 0.7 then magnitude of frictional force acting on the block will be
An inclined plane has an inclination θ with horizontal. A body of mass m rests on it. If the coefficient of friction between the body is µ, then the minimum force that needs to be applied parallel to the inclined plane is
Two blocks of mass M 1 and M 2 are connected with a string which passes over a smooth pulley. The mass M 1 is placed on a rough inclined plane as shown in fig. The coefficient of friction between the block and the inclined plane is µ. What should be the maximum mass M 2 so that block M 1 slides downwards ?
A block of mass m, placed on a horizontal surface is being pushed by a force F making an angle θ with the vertical. The coefficient of friction between block and the surface is µ. The force required to slide the block with uniform velocity on the floor is
What is the maximum value of the force F such that the block shown in fig. does not move ?
The upper half of an incline plane with inclination ϕ is perfectly smooth while the lower half is rough. A body starting from rest at top will again come to rest at the bottom if the coefficient of friction for the lower half is given by
A body is sliding down an inclined plane having coefficient of friction 0.5. If the normal reaction is twice that of the resultant downward force along the incline, the angle between the inclined plane and the horizontal is
The limiting friction between two surfaces a) depends on the nature of two surfaces b) is proportional to normal reaction c) is independent of apparent area of contact
Block of mass 1 kg is placed on a rough incline as shown. The coefficient of friction between block and incline is 0.4. The acceleration of block is (g = 10 ms –2 , √3 = 1.7)
A body of weight 64 N is pushed with just enough force to start it moving across a horizontal floor and the same force continues to act afterwards. If the coefficients of static and dynamic friction are 0.6 and 0.4 respectively, the acceleration of the body will be (Acceleration due to gravity = g)
A block B is pushed momentarily along a horizontal surface with an initial velocity V. If μ is the coefficient of sliding friction between B and the surface, block B will come to rest after a time
A uniform metal chain is placed on a rough table such that one end of chain hangs down over the edge of the table. When one-third of its length hangs over the edge, the chain starts sliding. Then, the coefficient of static friction is
A block of mass M = 5 kg is resting on a rough horizontal surface for which the coefficient of friction is 0.2. When a force F = 40 N is applied, the acceleration of the block will be (g = 10 ms 2 )
A block of mass 2Kg is kept on a rough horizontal surface. It is pulled by applying a horizontal force F μ s = 0.6 and μ k = 0.4 i) If F = 12 N, frictional force on the block is 7.84N ii) If F = 10 N, frictional force on the block is 10 N iii) If F = 7.84 N, frictional force on the block is zero
A block of mass 10 Kg pushed by a force F on a horizontal rough plane moves with an acceleration 5 m/s 2 . When the force is doubled, the acceleration becomes 18 m/s 2 , the coefficient of friction is (g = 10 m/s 2 )
A block of mass 10 Kg is on a rough horizontal table. The coefficient of friction between the block and table is 0.45, then frictional force on the block is (g = 10 m/s 2 )
A chain lies on a rough horizontal table. It starts sliding when one-fourth of its length hangs over the edge of the table. The coefficient of static friction between the chain and the surface of the table is
A man is running on ground the coefficient of friction between man and ground is μ . Assume that the center of mass of man moves horizontally Then which statement is incorrect :
A system consists of three masses m 1 , m 2 a n d m 3 connected by a string passing over a pulley P. The mass m 1 hangs freely and m 2 and m 3 are on a rough horizontal table (the coefficient of friction= μ ) The pulley is frictionless and of negligible mass. The downward acceleration of mass m 1 is (Assume m 1 = m 2 = m 3 = m
Which one of the following statements is incorrect?
In the figure, m A = 3kg and m B = 4 kg. For what minimum value of F, A starts slipping over B:(g = 10 m / s 2 )
A block of mass 10 kg is in contact against the inner wall of a hollow cylindrical drum of radius 1 m. The coefficient of friction between the block and the inner wall of the cylinder is 0.1 . The minimum angular velocity needed for the cylinder to keep the block stationary when the cylinder is vertical and rotating about its axis, will be g = 10 m / s 2
A block of mass m rests on truck accelerating at 4 m / s 2 . Block of mass m is 3m away from end of the truck. If coefficient of friction between block & truck surface is μ = 0 . 1 , the time taken by block to fall off the truck is
A plank with a box on it at one end is gradually raised about the other end. As the angle of inclination with the horizontal reaches 30°, the box starts to slip and slides 4.0m down the plank in 4.0 s. The coefficients of static and kinetic friction between the box and the plank will be, respectively
The upper half of an inclined plane of inclination θ is perfectly smooth while lower half is rough. A block starting from rest at the top of the plane will again come to rest at the bottom, if the coefficient of friction between the block and lower half of the plane is given by
A body of mass M is kept on a rough horizontal surface (friction coefficient μ ). A person is trying to pull the body by applying a horizontal force, but the body is not moving. The force by the surface on the body is F, where
A body of mass 8 kg lies on a rough horizontal table. It is observed that a certain horizontal force gives the body an acceleration of 4 m / s 2 . When this force is doubled, the acceleration of the body is 16 m / s 2 . The coefficient of friction is
A body of mass 2 kg is placed on a smooth horizontal surface. Two forces F 1 = 20 N a n d F 2 = 10 3 N are acting on the body in directions making angle of 30 0 and 60 0 to the surface. The reaction of the surface on the body will be
A body of mass m is kept on a rough horizontal surface (coefficient of friction = μ ). A horizontal force is applied on the body, but it does not move. The resultant of normal reaction and the frictional force acting on the object is given by F, where F is,
A block of mass m slides down an inclined plane which makes an angle θ with the horizontal. The coefficient of friction between the block and the plane is μ . The force exerted by the block on the plane is
In the arrangement shown, each of the blocks A and B has mass ‘m’ coefficient of friction between block B and table top is 0.5. The pulley is light then magnitude of reaction at the spindle of the pulley is
A car starts from rest to cover a distance S. The coefficient of friction between the road and the tyre is μ . The minimum time in which the car can cover the distance S is proportional to
A given object takes n times more time to slide down 45° rough inclined plane as it takes to slide down a perfectly smooth 45° incline. The coefficient of kinetic friction between the object and the incline is
As shown in figure, smaller block m and larger block M move together under the influence of a horizontal force P. The larger block M moves on a frictionless horizontal surface. If coefficient of static friction between the blocks M and m is 0.5. Find minimum value of P. For which the smaller block will not move relative to the larger block. Given m=1 kg, m=5 kg and g = 10 m / s 2
On a rough horizontal surface, a block of mass m is at rest. It suddenly receives a horizontal linear impulse J. How long it will continue to be in motion? Take g as the acceleration due to gravity and μ is the coefficient of kinetic friction.
A box of mass 8 kg is placed on a rough inclined plane of inclination θ . Its downward motion can be prevented by applying an upward pull F and it can be made to slide upwards by applying a force 2 F. The coefficient of friction between the box and the inclined plane is
A block of mass m is placed on another block of mass M which itself is lying on a horizontal surface. The coefficient of friction between the block of mass M and horizontal surface is μ 1 and that between the two blocks is μ 2 . What maximum horizontal force can be applied to the lower block so that the two blocks move without separation?
A block is placed over a plank which in turn is placed on a smooth level horizontal surface. The coefficient of friction between the block and plank is 0 . 2 . Initially both are at rest, suddenly the plank starts moving with accelerations a = 4 m s – 2 . The displacement of the block in 1sec is ( g = 10 m / s 2 ).
In the arrangement shown, mass of the object W is 3 kg, angle of friction between the object W and the inclined surface is 15 o . Then the minimum value of the horizontal force F for which the object W will remain in equilibrium is ( Take g = 10 m / s 2 )
AB is a thin rod of length l. Its moment of inertia about axis (1) is I 1 and that about axis (2) is I 2 . If I 1 > I 2 , and c be the position of centre of mass of the rod, then
In the arrangement shown, mass of the block is 5 kg and coefficient of static friction between the block and inclined surface is 0.2. For what minimum value of F, Will the block be on the verge of slipping down the plane ? Given tan 37 0 = 3 4 .
A block of mass 4 kg rests on rough horizontal surface. A vertically downward force P is applied on the block. The block just starts sliding when horizontal force P is applied on the block. If P = 1 2 mg , find the coefficient of friction between the block and the surface.
A block of mass 5 kg is placed on a horizontal surface with coefficient of friction μ = 0.2, then the maximum and minimum value of force F for which the block remains at rest are (g = 10 m / s 2 )
Two bodies of different masses are dropped simultaneously from same height. If air friction acting on them is directly proportional to the square of their mass, then ,
If the normal force is doubled and limiting frictional force is maintained at the same value, the coefficient of friction
A uniform rope of length L lies on a table. If the coefficient of friction is µ , the maximum fractional length of the hanging part of the rope from the edge of the table without sliding down is
In case of pulling & pushing minimum forces required are & then accelerations are (Here α = Angle of friction and θ is the angle with horizontal at which the force is applied).
A block of mass m is in contact with the cart C as shown in the figure. The coefficient of static friction between the block and the cart is µ . The acceleration α of the cart that will prevent the block from falling statisfies.
A scooter starting from rest moves with a constant acceleration for a time Δt 1 , then with a constant velocity for the next Δt 2 and finally with a constant deceleration for the next Δt 3 to come to rest. A 500 N man sitting on the scooter behind the driver manages to stay at rest with respect to the scooter without touching and other part. The force exerted by the seat on the man is
A homogeneous chain lies in limiting equilibrium on a horizontal table of coefficient of friction 0.5 with part of it hanging over the edge of the table. The fractional length of the chain hanging down the edge of the table is
The rear side of a truck is open and a box of 40 kg mass is placed 5 m away from the open end as shown in Figure. The coefficient of friction between the box the surface below it is 0.15. On a straight road the truck starts from rest and accelerates with 2 m s -2 . At what distance from the starting point does the box fall from the truck? (Ignore the size of the box).
An eraser weighing 2N is pressed against the black board with a force of 5N. If the coefficient of friction is 0.4. How much force parallel to the black board is required to slide the eraser upwards
A horizontal force of 10 N is necessary to just hold a block stationary against a wall. The coefficient of friction between the block and the wall is 0.2. The weight of the block is
A person just holds a block weighing 2kg between his hands & just keeps it from falling down by pressing it with his hands. If the force exerted by each hand horizontally is 50N, the coefficient of friction between the hand & the block is (g=10ms –2 )
A man of mass 40 kg is at rest between the walls as shown in the figure. If 'µ' between the man and the walls is 0.8, find the normal reaction exerted by the walls on the man. (g=10ms –2 )
A block B of mass 5kg is placed on a slab A of mass 20kg which lies on a frictionless surface as shown in the figure. The coefficient of static friction between the block and the slab is 0.4 and that of kinetic friction is 0.2. If a force F = 25N acts on B, the acceleration of the slab will be
A block slides down a slope of angle θ with constant velocity. It is then projected up with a velocity of 10 m s – 1 , g =10 m s – 2 & θ = 30º. The maximum distance it can go up the plane before coming to stop is
A body is allowed to slide from the top along a smooth inclined plane of length 5m at an angle of inclination 30º. If g = 10 m s – 2 , time taken by the body to reach the bottom of the plane is
Consider the following statements A) Angle of repose is equal to angle of friction B) Angle of friction is independent of coefficient of friction
A block of mass 'M' is pressed against a wall with a horizontal force F. Then a) it will slide down if the wall is smooth b) frictional force may balance the weight if the wall is rough c) Normal reaction is equal to weight of the block d) Normal reaction is zero if the wall is smooth
The system is pushed by a force F as shown in figure. All surfaces are smooth except between B and C. Friction coefficient between B and C is μ. Minimum value of F to prevent block B from downward slipping is
A box of mass 8 Kg is placed on a rough inclined plane of inclination θ . Its downward motion can be prevented by applying an upward pull F parallel to the inclined plane. And it can be made to slide upwards by applying a force 2F parallel to the inclined plane. The coefficient of friction between the box and inclined plane is
A body is projected up along an inclined plane from the bottom with speed v 1 . If it reaches the bottom of the plane with a velocity v 2 , find v 1 v 2 if θ is the angle of inclination with the horizontal and µ be the coefficient of friction.
The upper half an inclined plane of inclination θ is perfectly smooth while the lower half is rough. A block starting from rest at the top of the plane will again come to rest at the bottom. The coefficient of friction between the block and the lower half of the plane is given by
In this figure what force(F) should be applied on mass m = 5kg so that it just won't slip is (Given that car is moving with constant acceleration a = 5 m/s 2 and µ = 0.4)
A box of 100 kg is sliding down along a rough inclined plane of height 2m and length 4m. If coefficient of friction is 0.5 then the force required to be applied so that it comes down with a constant velocity is
In the arrangement shown, coefficient of friction between the block and the surface is 0.6 then
A 4 kg block is in equilibrium on a rough inclined surface having inclination of 30 o with horizontal. Then frictional force acting on the block is
The coefficient of friction between the 1.5 Kg block and the wall is 0.6. The block remains in equilibrium when a horizontal force of 30 N is applied on it. Then the frictional force acting on the block is
Two blocks A and B of masses m = 10 kg and M = 20 kg respectively are placed on each other and their combination rests on a fixed horizontal surface C. A light string passing over the smooth light pulley is used to contact A and B as shown. The coefficient of sliding friction between all surfaces in contact is μ = 1 4 . If A is dragged with a force F then for both A and B to move with a uniform speed , the value of F should be
The system is pushed by a force F as shown in figure. All surfaces are smooth except between B and C. Friction coefficient between B and C is μ . Minimum value of F to prevent block B from downward slipping is:
The coefficient of friction between the block and the horizontal surface is μ . The block moves towards right under action of horizontal force -F (figure-a). Sometime later another force P is applied to the block making an angle θ (such that tan θ = μ ) with vertical as shown in (figure-b). After application of force P, the acceleration of block shall
A block placed on a horizontal surface is being pushed by a force F making an angle θ with the vertical. The coefficient of friction between block and surface is μ . The force required to slide the block with uniform velocity on the floor is:
In the figure, a block of weight 60 N is placed on a rough surface. The coefficient of friction between the block and the surfaces is 0.5. What should be the weight W such that the block does not slip on the surface?
A block of mass m = 5 kg is resting on a rough horizontal surface for which the coefficient of friction is 0.2. When a force F = 40 N is applied, the acceleration of the block will be (g = 10 rn / s 2 )
A block of mass 2 kg is kept on the floor. The coefficient of static friction is 0.4. If a force F of 2.5 N is applied on the block as shown in the figure, the frictional force between the block and the floor will be
A block of mass l0 kg in contact against the inner wall of a hollow cylindrical drum of radius I m. The coefficient of friction between the block and the inner wall of the cylinder is 0.1. The minimum angular velocity needed for the cylinder to keep the block stationary when.the cylinder is vertical and rotating about its axis, will be (g = l0 m / s 2 )
A block A of mass m 1 rests on a horizontal table. A light string connected to it passes over a frictionless pulley at the edge of table and from its other end another block B of rnass m 2 is suspended. The coefficient of kinetic friction between the block and table is μ k When the block A is sliding on the table, the tension in the string is
A system consists of three masses m 1 , m 2 and m 3 connected by a string passing over a pulley P. The mass m, hangs freely and m 2 and m 3 are on a rough horizontal table (the coefficient of friction = μ ) The pulley is frictionless and of negligible mass. The downward acceleration of mass m 1 is (Assume m 1 = m 2 = m 3 = m)
ln the arrangement shown in figure, m A = m B = 2 kg . String is massless and pulley is frictionless. Block B is resting on a smooth horizontal surface, while friction coefficient between blocks A and B is μ = 0 . 5 The maximum horizontal force F that can be applied so that block.A does not slip over the block B is
A flat car is given an acceleration a 0 = 2 m / s 2 starting from rest. A cable is connected to a crate of weight 50 kg as shown whose other end is attached to a fixed support on ground. Neglect friction between the floor and the car wheels and also the mass of the pulley. Calculate corresponding tension in the cable if μ = 0.30 between the crate and the floor of the car.
Statement I: Pulling a lawn roller is easier than pushing it. Statement II: Pushing increases the apparent weight and hence the force of friction.
Two masses A and B of 10 kg and 5 kg respectively, are connected with a string passing over a frictionless pulley fixed at the corner of a table as shown in fig. the coefficient of friction of A with the table is 0.2. the minimum mass of C that may be placed on A to prevent it from moving is
A block A with mass 100 kg is resting on another block B of mass 200 kg. As shown in figure a horizontal rope tied to a wall holds it.The coefficient of friction between A and B is 0.2 while coefficient of friction between B and the ground is 0.3. The minimum required force F to start moving B will be
A 40 kg slab rests on a frictionless floor as shown in the figure. A l0 kg block rests on the top of the slab. The static coefficient of friction between the block and slab is 0.60 while the kinetic friction is 0.40. The l0 kg block is acted upon by a horizontal force 100 N. If g = 9.8 m / s 2 , the resulting acceleration of the slab will be
Blocks A ard B in the figure are connected by a bar of negligible weight. Mass of each block is 170 kg and μ A = 0 . 2 and μ B = 0 . 4 , where μ A and μ B are the coefficients of limiting friction between blocks and plane, calculate the force developed in the bar (g = 10 m / sec 2 ):
The minimum acceleration that must be imparted to the cart in the figure so that the block A will not fall (given μ is the coefficient of friction between the surfaces of block and cart) is given by:
A block of mass 1 kg is at rest on a horizontal table. The coefficient of static friction between the block and the table is 0.5. The magnitude of the force acting upwards at an angle of 60° from the horizontal that will just start the block moving is
Figure shows two blocks A and B pushed against the wall with the force F. The wall is smooth but the surfaces in contact of A and B are rough. Which of the following is true for the system of blocks to be at rest against wall?
A force of 100 N is applied on a block of mass 3 kg as shown in the figure. The coefficient of friction between the surface and the block is μ = 1 3 . The acceleration of block is
A block pressed against the vertical wall is in equilibrium.if μ = 0.3, the acceleration of the block will be:
A force of 100 N is applied on a block of mass 3 kg as shown in the figure. The coefficient of friction between the surface and the block is μ = 1 3 . The frictional force acting on the block is
A rectangular body is held at rest by pressing it against a vertical wall for which μ < l. Which of the following is generally true?
A horizontal force F acts on the block of mass m and the block remains stationary, if we pull the block by the force F making an angle θ and the block remains stationary, the value of friction force is
A block pressed against the vertical wall is in equilibrium. The minimum coefficient of friction is:
A block of weight W is held in equilibrium against a vertical wall by applying a horizontal force of 75 N. The surface of the wall is rough. Now, (consider μ < l)
A block of mass m is stationary on a horizontal surface. It is connected with a string which has no tension. The coefficient of friction between the block and surface is m. Then, the frictional force between the block and surface is:
A horizontal force F acts on the block of mass m and the block remains stationary, the minimum force F required to pull it( μ = 1 2 ) is:
A horizontal force F acts on the block of mass m and the block remains stationary, if we pull the block by the force F making an angle θ and the block remains stationary, the value of friction force is
In the track shown in figure section AB is a quadrant of a circle of I metre radius. A block is released at A and slides without friction until it reaches B. After B it moves on a rough horizontal floor and comes to rest at distance 3 metres from B. What is the coefficient of friction between floor and body?
In the diagram shown, if coefficient of static friction between the block and the surface is 0.4, the limiting friction will be
A block has been placed on an inclined plane. The slope angle θ of the plane is such that the block slides down the plane at a constant speed. The coefficient of kinetic friction is equal to:
A block takes twice as much time to slide down a 45° rough inclined plane as it takes to slide down a similar smooth plane. The coefficient of friction is:
A rough vertical board has an acceleration ‘a’ so that a 2kg block pressing against it does not fall. The coefficient of friction between the block and the board should be:
A block released from rest from the top of a smooth inclined plane of inclination 45° takes time ‘t’ to reach the bottom. The same block released from rest, from top of a rough inclined plane of same inclination, takes time ‘2t’ to reach the bottom, coefficient of friction is:
In figure coefficient of friction between m 1 and m 2 is μ and that between m 1 and the wall is zero. A force F is pressing the system against the wall. Minimum value of force required to hold the system in equilibrium if coefficient of friction between m 1 and the wall is μ, and, f 1 and f 2 are, respectively, the force of friction on m 1 and m 2 ,then:
In Figure, coefficient of friction between the block and the floor is ‘ μ ‘. Force F that will move the block on the floor with a uniform speed is
In Figure, coefficient of kinetic friction between the 4 kg block and the inclined surface is 1 3 . Here ‘m’ is such a mass that the 4 kg block is moving up the plane with a constant speed, then m is:
A uniform rope of length I lies on a table. If the coefficient of friction is ‘ μ ‘, then the maximum length l 1 of the part of this rope which can overhang from the edge of the table without sliding down is:
The upper half of an inclined plane with inclination ϕ is perfectly smooth while the lower half is rough. A body starting from rest at the top will again come to rest at the bottom, if coefficient of friction for the lower half is given by:
A force F pushes a block weighing l0 kg against a vertical wall as shown in the Figure. The coefficient of friction between the block and wall is 0.5. The minimum value of F to start the upward motion of block is : (g = 10m/s 2 )
A block rests on a rough inclined plane making an angle of 30° with the horizontal. The coefficient of static friction between the block and the plane is 0.8. If the frictional force on the block is 10 N, the mass of the block (in kg) is : (take g = 10 m/s 2 )
Two blocks, 4 kg and 2 kg are sliding down an incline plane as shown in Figure. The acceleration of 2 kg block is:
A mass of 1 kg is just able to slide down the slope of an inclined rough surface when the angle of inclination is 60°. The minimum force necessary to pull the mass up the inclined plane is : (g = l0 ms -2 )
A body of mass m slides down an inclined plane making an angle of 45° with the horizontal. If the coefficient of friction between the body and the plane be 0.3, the acceleration of the body is approximately equal to :
A block of mass m is in contact with the cart C as shown in the Figure. The coefficient of static friction between the block and the cart is μ . The acceleration s of the cart that will prevent the block from falling satisfies :
A plank with a box on it at one end is gradually raised about the other end. As the angle of inclination with the horizontal reaches 30°, the box starts to slip and slides 4.0 m down the plank in 4.0 s. The coefficients of static and kinetic friction between the box and the plank will be, respectively :
A force F equals to 100 N is applied on 30 kg box inside which a 10 kg mass is hanging with the help of a massless string as shown in figure. Coefficient of friction between box and surface is 0.1. Initially system is at rest, then at this instant acceleration of box will be
A car moves uniformly along a horizontal sine curve y = a sin ( x α ) , where a and α are certain constants. The coefficient of friction between the wheels and the road is equal to k. The maximum constant speed at which the car can travel without sliding is
The coefficients of static and dynamic friction are 0.7 and 0.4. The minimum force required to create motion is applied on a body and if it is further continued, the acceleration attained by the body in ms –2 is (g = 10m/s 2 )
The coefficient of static friction between contact surfaces of two bodies is 1. The contact surfaces of one body support the other till the inclination is less than
A book of weight 20N is pressed between two hands and each hand exerts a force of 40N. If the book just starts to slide down. Coefficient of friction is
A block of mass 20 kg is pushed with a horizontal force of 90N. If the coefficient of static and kinetic friction are 0.4 and 0.3, the frictional force acting on the block is (g =10ms -2 )
The angle of inclination of an inclined plane is 60º. Coefficient of friction between 10kg body on it and its surface is 0.2, g = 10 ms –2 . The acceleration of the body down the plane in ms –2 is
When a body slides down an inclined plane with coefficient of friction as μ k , then its acceleration is given by
A brick of mass 2kg just begins to slide down on inclined plane at an angle of 45º with the horizontal. The force of friction will be
The lengths of smooth & rough inclined planes of inclination 45° is same. Times of sliding of a body on two surfaces is t 1 ,t 2 and m = 0.75, then t 1 : t 2 =
A block of weight 200N is pulled along a rough horizontal surface at constant speed by a force of 100N acting at an angle 30º above the horizontal. The coefficient of kinetic friction between the block and the surface is
A duster weighs 0.5N. It is pressed against a vertical board with a horizontal force of 11N. If the co-efficient of friction is 0.5 the minimum force that must be applied on the duster parallel to the board to move it upwards is
A vehicle of mass M is moving on a rough horizontal road with a momentum P. If the coefficient of friction between the tyres and the road is μ , then the stopping distance is
The rear side of a truck is open and a box of 40 kg mass is placed 5 m away from the open end as shown in figure. The coefficient of friction between the box the surface below it is 0.15. On a straight road, the truck starts from rest and accelerates with 2 ms -2 . At what distance from the starting point does the box fall from the truck? (Ignore the size of the box.)
A block A of mass 3kg and another block B of mass 2 kg are connected by a light inextensible string as shown in figure. If the coefficient of friction between the surface of the table and A is 0.5. What maximum mass C is to be placed on A so that the system is to be in equlibrium?
Which of the following statements is correct about friction?
A smooth block is released from rest on a 4 5 o inclined plane and it slides a distance ‘d’. The time taken to slide is n times that on a smooth inclined plane. The coefficient of friction
The upper half of an inclined plane of inclination ‘ θ ‘ is perfectly smooth while the lower half is rough. A block starting from rest at the top of the plane will again come to rest at the bottom. The coefficient of friction between the block and the lower half of the plane is given by
A 30 kg box has to move up an inclined plane of slope 30° to the horizontal with a uniform velocity of 5 ms -1 .If the frictional force retarding the motion is 150N, the horizontal force required to move the box up is(g=10ms -2 )
A pulling force making an angle θ with the horizontal is applied on a block of weight W placed on a horizontal table. If the angle of friction is ϕ , the magnitude of the force required to move the body is equal to
A block of mass 3 kg is kept on a frictional surface with μ = 1 2 3 . The minimum force to be applied as shown to move the block is
A particle is placed at rest inside a hollow hemisphere of radius R. The coefficient of friction between the particle and the hemisphere is μ = 1 3 . The maximum height up to which the particle can remain stationary is
A man slides down on a telegraphic pole with an acceleration equal to one-fourth of acceleration due to gravity. The frictional force between man and pole is equal to (in terms of man’s weight W)
A box is placed on the floor of a truck moving with an acceleration of 7 ms -2 . If the coefficient of kinetic friction between the box and surface of the truck is 0.5,find the acceleration of the box relative to the truck
A block is placed at a distance of 2m from the rear on the floor of a truck (g=10ms -2 ). When the truck moves with an acceleration of 8ms -2 , the block takes 2 sec to fall off from the rear of the truck. The coefficient of sliding friction between truck and the block is
A body is projected up along an inclined plane from the bottom with speed is 2v. If it reaches the bottom of the plane with a velocity v, if θ is the angle of inclination with the horizontal and μ be the coefficient of friction.
A box of mass 4 kg is placed on a rough inclined plane of inclination 60°. Its downward motion can be prevented by applying an upward pull is F and it can be made to slide upwards by applying a force 3F. The coefficient of friction between the box and inclined plane is
A body takes 1 1 3 times as much time to slide down a rough inclined plane as it takes to slide down an identical but smooth inclined plane. If the angle of inclination is 45°, find the coefficient of friction.
A body is sliding down an inclined plane having coefficient of friction 1/3. If the normal reaction is three times that of the resultant downward force along the inclined plane, the angle between the inclined plane and the horizontal is
A block of weight 100N is lying on a rough horizontal surface. If coefficient of friction 1 3 . The least possible force that can move the block is
A body slides over an inclined plane forming an angle of 4 5 o with the horizontal. The distance x travelled by the body in time t is described by the equation x = kt 2 , where k = 1.732. The coefficient of friction between the body and the plane has a value
A block of mass 4kg is placed in contact with the front vertical surface of a lorry. The coefficient of friction between the vertical surface and block is 0.8.The lorry is moving with an acceleration of 15 m/ s 2 .The force of friction between lorry and block is (g =10 ms -2 )
A block has been placed on an inclined plane. The slope angle θ of the plane is such that the block slides down the plane at a constant speed. The coefficient of kinetic friction is equal to
Two masses A and B of 10 kg and 5 kg respectively are connected with a string passing over a frictionless pulley fixed at the corner of a table as shown in figure. The coefficient of friction of A with the table is 0.2. The minimum mass of C that may be placed on A to prevent it from moving is equal to
Starting from rest, a body slides down a 45 0 inclined plane in twice the time, it takes to slide down the same distance in the absence of friction. The coefficient of friction between the body and the inclined plane is
A block of mass 5 kg resting on a horizontal surface is connected by a cord, passing over a light frictionless pulley to a hanging block of mass 5 kg. The coefficient of kinetic friction between the block and the surface is 0.5. Tension in the cord is (Take, g = 9.8 ms -2 )
In the figure shown, if coefficient of friction is μ , then m 2 will start moving upwards, if
Block A of mass m rests on the plank B of mass 3m which is free to slide on a frictionless horizontal surface. The coefficient of friction between the block and plank is 0.2. If a horizontal force of magnitude 2 mg is applied to the plank B , the acceleration of A relative to the plank and relative to the ground respectively, are
Directions : These questions consists of two statements each printed as Assertion and Reason. While answering these questions you are required to choose any one of the following four responses Assertion : In the system of two blocks of equal masses as shown, the coefficient of friction between the blocks ( μ 2 ) is less than coefficient of friction μ 1 ) between lower block and ground. For all values of force F applied on upper block, lower block remains at rest. Reason : Frictional force on lower block due to upper block is not sufficient to overcome the frictional force on lower block due to ground.
Directions : These questions consists of two statements each printed as Assertion and Reason. While answering these questions you are required to choose any one of the following four responses Assertion : In the system of two blocks of equal masses as shown, the coefficient of friction between the blocks ( μ 2 ) is less than coefficient of friction μ 1 ) between lower block and ground. For all values of force F applied on upper block, lower block remains at rest. Reason : Frictional force on lower block due to upper block is not sufficient to overcome the frictional force on lower block due to ground.
In the diagram shown in figure, match the following columns (Take, g = 10 ms -2 ) Column I (A) Normal reaction (8) Force of friction (C) Acceleration of block Column II (p) 12 SI unit (q) 20 SI unit (r ) zero (s) 2 SI unit
A body of mass m is kept on a rough horizontal surface (coefficient of friction = μ ). Horizontal force is applied on the body, but it does not move. The resultant of normal reaction and the frictional force acting on the object is given F , where F is [NEET (Odisha) 2019]
A body of mass 5 X 10 -3 kg is launched upon a rough inclined plane making an angle of 30° with the horizontal. Obtain the coefficient of friction between the body and the plane, if the time of ascent is half of the time of descent.
A box of mass 8 kg is placed on a rough inclined plane of inclination 30°. Its downward motion can be prevented by applying a horizontal force F , then value of F for which friction between the block and the incline surface is minimum, is
To determine the coefficient of friction between a rough surface and a block, the surface is kept inclined at 45° and the block is released from rest. The block takes a time t in moving a distance d . The rough surface is then replaced by a smooth surface and the same experiment is repeated. The block now takes a time t /2 in moving down the same distance d . The coefficient of friction is
A body of mass m is placed on a rough surface with coefficient of friction μ inclined at θ . If the mass is in equilibrium, then
A 40 kg slab rests on a frictionless floor. A 10 kg block rests on the top of the slab as shown in figure. The static coefficient of friction between the block and the slab is 0.60 while the kinetic coefficient is 0.40. The 10 kg block is acted upon by a horizontal force of 100 N. If g = 9.8 m s – 2 , the resulting acceleration of the slab will be
An inclined plane of height h and length l have the angle of inclination θ . The time taken by a body to come from the top to the bottom of this inclined plane will be
A block A of mass 100 kg rests on another block B of mass 200 kg and is tied to a wall as shown in the figure. The coefficient of friction between A and B is 0.2 and that between B and the ground is 0.3. The minimum force F required to move the block B is (Take, 9 = 10 m s – 2 )
A body of weight 50 N placed on a horizontal surface is just moved by a force of 282 N. The frictional force and normal reaction are
A block slides down an inclined plane of slope of angle q with a constant velocity v’ It is then projected up the plane with an initial velocity u. the distance upto which it will rise before coming to rest is
A 40 kg slab rests on frictionless floor as shown in fig. A 10 kg block rests on the top of the slab. The static coefficient of friction between the block and slab is 0.60 while the kinetic friction is 0.40. The 10 kg block is acted upon by a horizontal force 100 N. If g = 9.8 m / s 2 , the resulting acceleration of the slab will be
A body having kinetic energy K moving on a rough horizontal surface is stopped in a distance x. The force of friction exerted on the body is
A block of mass m, lying on a rough horizontal plane, is acted upon by a horizontal force P and another force Q inclined at an angle q to the vertical. The block will remain in equilibrium, if the coefficient of friction between it and the surface is
A block of mass 0 . 5 kg has an initial velocity of 10 m/s down an inclined rough plane of angle 30 0 as shown in fig. (6). The coefficient of friction between the block and inclined surface being 0 2. The velocity of the block after it travels a distance of 10 m is
A block of mass m is placed on the top of another block of mass M as shown in fig., The coefficient of friction between them is µ. What is the maximum acceleration with which the block M may move so that m also moves along it ?
Block A is placed on block B whose mass is greater than that of A. There is friction between the blocks while the ground is smooth. A horizontal force P (see the figure), increasing linearly with time, begins to act on the upper block The accelerations a 1 and a 2 of A and B respectively are plotted against time t . Choose the connect graph [Fig].
An object is kept on a smooth inclined plane of 1 in l. The horizontal acceleration to be imparted to the inclined plane so that the object is stationary relative to the incline is given by
A block of mass m is placed on another blocks of mass M which itself is lying on a horizontal surface. The coefficient of friction between the two blocks is µ 1 and that between the block of mass M and horizontal surface is pr. What maximum horizontal force can be applied to the lower block so that the two blocks move without separation ?
An insect crawling up a fixed hemispherical bowl of radius .R. If the coefficient of friction is 1 3 , then the insect can only crawl upto a height of
A block of mass 5 kg slides down a rough inclined surface. The angle of inclination is 45 0 . The coefficient of sliding friction is 0.20 . When the block slides 10 cm, the work done on the block by force of friction is
A block of mass M 1 = 10 kg is placed on a slab of mass M 2 =30kg, The slab lies on a frictionless horizontal surface as shown in fig. The coefficient of static friction between the block and slab is µ 1 =0.5 and that of dynamic friction is µ 2 =0.15.A force F =40N acts on block M 1 . What will be the acceleration with which the slab will move? (Take g = 10 m / s 2 )
The minimum acceleration that must be imparted to the cart in fig., so that the block A will not fall, given µ is the coefficient between the surfaces of block and cart
A block of mass 2 kg is placed on the floor. The coefficient of static friction is 0.4 A force F of 2.5 N is applied on the block as shown in fig. The force of friction between the block and the floor is ( g = 9 ⋅ 8 m / s 2 )
Two blocks of mass M 1 and M 2 are connected with a string passing over a pulley as shown in fig. The block M 1 lies on a horizontal surface. The coefficient of fiction between the block M and the horizontal surface is µ. The system accelerates. What additional mass m so that the system does not accelerate ?
Two blocks A(2 kg) and B(5 kg) rest one over the other on a smooth horizontal plane. The coefficient of static and dynamic friction between A and B is the same and is equal to 0.60. The maximum horizontal force that can be applied to B in order that both A and B do not have relative motion is TAKE g= 10 ms -2
A block of mass m is placed in contact with another block of mass M as shown in fig. The coefficient of friction between the blocks is µ. With what acceleration the block M should move so that the block m does not slide down ?
A marble block of mass 2 kg lying on ice when given a velocity of 6 m/s is stopped by friction in 10 s. Then the coefficient of friction is
A block rests on a rough inclined plane making an angle of 30° with the horizontal. The coefficient of static friction between the block and the plane is 0.8. If the frictional force on the block is 10 N, the mass of the block (in kg) is (take g = 10 m/s 2 )
Which is true for rolling friction (µ r ), static friction (µ s ) and kinetic friction (µ k ) ?
In a certain machine at a fun fair, a man stands against the wall of a circular room of radius 3 m. The room rotates about a vertical axis through the centre of the floor at 2 rad/sec., then the floor is lowered- If the man does not slip vertically downwards, the least value of the coefficient of friction between the man and wall is
A skier starts from rest at point A and slides down the hill without turning or breaking. The friction coefficient is μ . When he stops at point B , his horizontal displacement is s. What is the height difference between points A and B ? (The velocity of the skier is small, so that the additional pressure on the snow due to the curvature can be neglected. Neglect also the friction of air and the dependence of μ on the velocity of the skier.)
A 2 kg block of wood rests on a long table top. A 5 g bullet moving horizontally with a speed of 150 ms – 1 is shot into the block and sticks to it. The block then slides 2.7 m along the table top and comes to a stop. The force of friction between the block and the table is
A man is running on ground the coefficient of friction between man and ground is μ . Assume that the center of mass of man moves horizontally Then which statement is incorrect :
A man is running on ground the coefficient of friction between man and ground is μ . Assume that the center of mass of man moves horizontally Then which statement is incorrect :
A body of mass 60 Kg is pushed with just enough force to start it moving on a rough horizontal surface with μ S = 0 .5 and μ k = 0 .4 and the force continues to act afterwards. The acceleration of the body is
A box of mass 9kg is placed on a rough inclined plane of inclination θ . Its downward motion can be prevented by applying an upward pull of 20N and it can be made to slide upwards by applying a force 40N. The coefficient of friction between the box and the inclined plane is
A chain lies on a rough horizontal table. It starts sliding when one-fourth of its length hangs over the edge of the table. The coefficient of static friction between the chain and the surface of the table is
To avoid slippping while walking on ice, one should take smaller steps because of the
A body is projected along a rough horizontal surface with a velocity 6 m/s. If the body comes to rest after travelling a distance of 9 m, the coefficient of sliding friction is (g = 10 m/s 2 )
If the normal force is doubled, the coefficient of friction is
In Figure, coefficient of friction between the block and the floor is ‘µ’. Force F that will move the block on the floor with a uniform speed is
A stone weighing 1 kg and sliding on ice with a velocity of 2 m/s is stopped by friction in 10 sec. The force of friction (assuming it to be constant) will be
A uniform rope of length L lies on a table. If the coefficient of friction is µ, then the maximum length l 1 of the part of this rope which can overhang from the edge of the table without sliding down is:
In the figure given, the system is in equilibrium. What is the maximum value that W can have if the friction force on the 40 N block cannot exceed 12.0 N
A car is moving along a straight horizontal road with a speed u 0 . If the coefficient of friction between the tyres and the road is μ , the shortest distance in which the car can be stopped is
A block is kept on an inclined plane of inclination θ of length l. The velocity of particle at the bottom of inclined plane is (the coefficient of friction is μ )
A body of mass 10 kg is lying on a rough plane inclined at an angle of 30° to the horizontal and the coefficient of friction is 0.5. The minimum force required to pull the body up the plane is
A number of coins each of mass 400g are placed one over the other. The minimum horizontal force required to pull the eight coin from the top without disturbing the remaining is 10N g = 10m/s 2 . The coefficient of friction between any two coins is
A man is running on ground. The coefficient of friction between man and ground is 0.25. Assume that the center of mass of man moves horizontally. Then which statement is incorrect :
A body of weight 64 N is pushed with just enough force to start and move it across a horizontal floor and the same force continues to act afterwards. If the coefficients of static and dynamic friction are 0.6 and 0.4 respectively, the acceleration of the body will be (Acceleration due to gravity = g)
A body is projected along a rough horizontal surface with a velocity 6 m/s. If the body comes to rest after travelling a distance of 9 m, the coefficient of sliding friction is (g = 10 m/s 2 )
Aeroplanes are streamlined to reduce
A body of mass 60 Kg is pushed with just enough force to start it moving on a rough horizontal surface with µ s = 0.5 and µ k = 0.4 and the force continues to act afterwards. The acceleration of the body is
A block B is pushed momentarily along a horizontal surface with an initial velocity V. If μ is the coefficient of sliding friction between B and the surface, block B will come to rest after a time
To avoid slipping while walking on ice, one should take smaller steps because of the
An insect is at the bottom of a hemispherical ditch of radius 1 m. It crawls up the ditch but starts slipping after it is at height h from the bottom. If the coefficient of friction between the ground and the insect is 0.75, then h is g = 10 ms − 2 .
