Question

A body of mass 5 kg is moving with a momentum of 10 kgm/s. If a force of 0.2 N acts on it in the direction of motion of body for 10 sec . The increase in Kinetic energy is

3.2J
3.8J
4.4J
2.8J​

Answer 1

Answer:

mass = 5kg

momentum = 10kgm/s

velocity = 2m/s

kinetic energy = ½mv²

= 10J

We know, 1N(F) = 1kg(M) × 1m(d)

So, F/M = d

0.2/5 = d

d = 1/25m

u = 2m/s

t = 10s

a = 1/25m/s²

v = u+at

= 2 + 10/25

= 60/25

= 2.4m/s

therefore, final kinetic energy = ½mv²

= ½ × 5 × 2.4²

= 5×2.88

= 14.4J

change in kinetic energy or work done =

KE(final) - KE(initial)

= 14.4-10

= 4.4J

Hope it helped :)