Question

A body of mass 2 kg moving on a horizontal surface with an initial velocity of 4 m per sec comes at rest after 2 sec if one wants to keep this body moving on the same surface with the velocity of 4 m per sec what is the force

Answer 1

Force = mass × acceleration

Acceleration = Change in velocity / Change in time

Change in velocity = Final velocity - initial velocity

Change in velocity = 0 - 4 = - 4m/s

The negative sign indicates that the body is decelerating.

Deceleration = - acceleration

Acceleration = - 4/2 = - 2m/s²

This is 2m/s² (we take the absolute value)

Force = 2 × 2 = 4 N