Given in the figure are two blocks of A and B of weight $20 N$ and $100 N,$ respectively. These are being pressed against a wall by a force $F$ as shown. If the coefficient of friction between the blocks is $0.1$ and between block B and the wall is $0.15,$ the frictional force applied by the wall on block B is:

see full answer

Start JEE / NEET / Foundation preparation at rupees 99/day !!

21% of IItians & 23% of AIIMS delhi doctors are from Sri Chaitanya institute !!

An Intiative by Sri Chaitanya

$120 N$

$150 N$

$100 N$

$80 N$

answer is A.

(Unlock A.I Detailed Solution for FREE)

Ready to Test Your Skills?

Check your Performance Today with our Free Mock Test used by Toppers!

Take Free Test

Detailed Solution

As the both the masses are in equilibrium the static friction will be acting on blocks which can be found from balancing the forces in vertical direction.
The FBD of block A
Writing force balance in vertical direction for block A, $f_{1}$ = weight of the block A =20 N

Writing force balance in vertical direction for block B

$f_{1} - f_{2}$ = weight of the block B 100 N

The value of frictional force between wall and block B is 120 N