Question

A block of mass 1 kg on a horizontal surface in a truck. The coefficient of static friction between the block and the surface is 0.6 if the acceleration of the truck is $5,m{s}^2$, the frictional force acting on the block is

• A. 5 N
• B. 6 N
• C. 10 N
• D. 15 N

Answer 1

The correct option is A 5 N

Answer is A.

As the truck is accelerating, let it be in the forward direction.o the block will experience a pseudo force in the backward direction. In order to oppose the motion of acceleration of the block, the frictional force acts on the block.
Let us take g = $10m/s^2$.
$F_s=\mu N$ where $\mu$ is the coefficient of friction and N is the normal force = mg.
Therefore, $F_s=\mu mg=0.6\times 1\times 10=6N$.
Also, $F_s=ma=1\times 5=5N$.
As 5 N is required to oppose the motion of the block, so the frictional force acting on the block is 5 N.