Question

The force of friction acting on a body when velocity is $4m{s}^{-1}$ is $8N$. The force of friction when the velocity is $8m{s}^{-1}$ is

• A. 4 N
• B. 8 N
• C. 16 N
• D. 32 N

Answer 1

The correct option is B 8 N

When the body is in motion, the frictional force acting on it is kinetic friction
$f{}_k=\mu {}_{k}N$ which is independent of the velocity with which the body is moving.

So the frictional force remains the same when the velocity changes from $4m{s}^{-1}$ to $8m{s}^{-1}$ i.e, $8N$.