BlogNEETStatic and Kinetic Friction

Static and Kinetic Friction

What is Friction?

As soon as we throw a ball on the floor, it starts moving with some speed. However, preferably, no power ought to be acting toward movement, and as per Newton’s first law, the ball should continue to roll, yet this doesn’t occur. All things considered, the ball stops subsequent to moving a specific distance, so power should be following up on it. We refer to this power as “grinding.”

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    Rubbing is characterized as the opposition presented by the surfaces that are in contact when they move past one another. Contact gives footing that is expected to stroll without slipping. Contact is useful much of the time. They additionally offer a great deal of resistance to the movement. In addition, around 20% of the motor force of autos is used to overcome frictional forces.

    As the expert, everything being equal, friction is one significant component regarding that situation and in nature. Friction is essentially characterised as the energy by which opposition is met when objects, strong surfaces or materials interact with one another in a sliding or coasting movement. Friction comes in a few sorts which similarly have three properties named laws. Friction is significant on the grounds that it permits a decent handle and stronghold on things or to a surface to keep a specific position and to start development. Without friction, each current material and being contained in the planet can’t support any sorts and sorts of development and will constantly slip and fall fundamentally on the grounds that the reason for contact is with regards to the resistance.

    Factors Affecting Friction

    Friction is a force that is influenced by external factors. There are two main factors that affect friction.

    Characteristics of the surfaces that come into contact:

    Friction is subject to the perfection or unpleasantness of the two surfaces that are in touch with one another. At the point when the surface is smooth, the rubbing between the two decreases as there isn’t a lot of interlocking of abnormalities. While the surface is harsh, grating increments.

    Considering the forces that act on these surfaces: As the force is applied along with irregularities, friction increases.

    Types of Friction

    Among the four types of friction, there are the following:

    1. Static friction
    2. Sliding friction
    3. Rolling friction
    4. Fluid friction

    Every one of the four kinds of frictions is not the same as one another. For instance, static friction is the friction that is demonstrated between the surfaces when they are very still concerning one another. Interestingly, sliding friction is the obstruction made between any two articles while sliding against one another.

    Static Friction

    As the name implies, static friction is the friction between surfaces when they are at rest with respect to each other.

    Static force is equal in magnitude in the opposite direction when a small amount of force is applied. As the force increases, static friction reaches its maximum point.

    Static Friction Examples

    Following are the examples of static friction:

    1. Skiing against the snow
    2. Creating heat by rubbing your hands together
    3. Table lamp resting on the table

    Coefficient Of Static Friction

    The coefficient of static friction is indicated as µs. The most extreme power of static friction is derived from the coefficient of static friction, and the ordinary power and the power of static friction are not exactly or equivalent to the coefficient of static friction and the typical power. It is given as:

    F s max = μsη and F s ≤ μsη


    1. F s is the force of static friction
    2. µs is the coefficient of static friction
    3. η is the normal force
    4. F s max is the maximum force of static friction

    What is Kinetic Friction?

    Kinetic friction is characterized as a power that acts between moving surfaces. A body continuing on a superficial level encounters a power the other way of its development. The extent of the power will rely upon the coefficient of kinetic friction between the two materials.

    Kinetic friction is a piece of everything and it meddles movement of at least two items. The power acts the other way to the manner in which an article needs to slide. Assuming a vehicle needs to stop, we apply brakes and that is by and large where the friction becomes possibly the most important factor.

    While walking, when one needs to unexpectedly stop, friction is to thank once more. Be that as it may, when we need to stop in a puddle, things get more earnestly since friction is less there and can’t help one to such an extent.

    Kinetic Friction Formula

    By sub-scripting “k” to the Greek letter “mu” (*), one can denote the coefficient of kinetic friction. Kinetic friction increases the normal force on a body by *k times. It is expressed in Newtons (N). The kinetic friction equation is as follows:

    The force of kinetic friction is equal to (the coefficient of kinetic friction)(the normal force)

    F k = μk η


    1. F k = force of kinetic friction
    2. μk = coefficient of kinetic friction
    3. η = normal force

    Applications of Kinetic Friction

    1. Friction also plays an important role in everyday occurrences, such as when two objects rub against each other. Some of the resulting motion is converted into heat, resulting in fire.
    2. Additionally, oil reduces friction, which is why we need it to lubricate machine parts.
    3. As two objects rub against each other, frictional force is converted into thermal energy, sometimes leading to a fire.
    4. Kinetic friction is responsible for machine wear and tear, so it is important to lubricate the machine parts with oil.

    File:Friction forces.jpg

    Also read: Laws of friction

    Frequently Asked Questions FAQ’s:

    Que: How does friction produce heat?

    Ans: Surfaces in contact convert kinetic energy into heat through friction when they move relative to each other.

    Que: Why is friction a non-conservative force?

    Ans: Friction is a non-conservative force since the amount of work it does depends on the path.

    Que: Can friction be zero?

    Ans: Every surface has minor irregularities regardless of how much lubricant is applied, so there is no such thing as zero friction.

    Que: What are some examples of kinetic friction?

    Ans: There’s a rock rolling off a slope, a football rolling, and a roller skater on the move.

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