Question

You are holding a block 'A' with your palms. Each of your palm is giving, F = 12 N force to the block as shown in the figure. The weight of the block is W = 8 N. The block is not sliding. So the frictional force on the block by each of your palm will be _________.

• A. 12 N
• B. 8 N
• C. 20 N
• D. 4 N

Answer 1

The correct option is D 4 N

The block is not sliding. So static friction is acting on the block. The frictional force will act in the upward direction to balance the weight of the block.
So total frictional force on the block
= Weight of the block
= $8N$.

Frictional force by each of your palm is equal (as normal forces (F) are equal)
So, frictional force by each of your palm = $\frac{8}{2}N$
= $4N$.