Question

A force acts for 10 s on a stationary body of mass 100 kg after which the force ceases to act. The body moves through a distance of 100 m in the next 5 seconds calculate velocity, acceleration and the magnitude of force

Answer 1

A force acts on a stationary body for 10 s and stops. After the force stops to act on the body, it covers a distance of 100 m in 5 s. We are required to find the (uniform) acceleration on the body due to force.

To solve this problem, we need to remember that after a force stops to act, the body will move with uniform velocity ( ignoring friction). Since the body covers 100 m in 5 s, its velocity at the end of acceleration period is,

v = 100 m/ 5 s = 20 m/s.

This final velocity has happened due to the force producing acceleration on the stationary body for 10 seconds. Using the relation,

v = u + a t ,

we have, u = 0 m/ s, v = 20 m/s, we get,

a = ( 20 m/s - 0 m/s) / 10 s = 2 m/s².

So the acceleration on the body is 2 m/s².