Question

A body of mass 5 kg has momentum of 10 kg m/s. When a force of 0.IN is applied on it for 10 seconds, the change in
its kinetic energy is:​

Answer 1

Answer:

Explanation:

Initial momentum is 10 kgm/s.

Mass × velocity = 5 × v = 10.

So v = 2m/s

Force = mass × acceleration

0.2 = 5 × accln. So accln. is 0.04 m/s/s

Assuming that the force acts in the same direction, velocity of 2 m/s will increase in 10 sec by 0.04 × 10 = 0.4 m/s and becomes 2.4 m/s.

So change in KE is 0.5 × ( 2.4^2 - 2^2)

This comes to 4.4 joules.

If the force acts in the opposite direction, the velocity of 2 will become 1.6 m/s and change in KE = 3.6 J.