Question

if the body of mass 5 kg has a momentum of 10 kgm/s , force applied of 0.2 N for 10 sec then find the change in kinetic energy

Answer 1

Initial momentum = 10 kgm/s
Mass * Initial velocity = 10
Initial velocity = 10/5 = 2 m/s

Now,
Force = Change in Momentum / Time
Therefore,
0.2 = m(Final velocity - Initial velocity) / Time
0.2*10 = 5(v-2)
v-2 = 0.4
v = 2.4 m/s

Now , you can easily find out change in kinetic energy by
1/2*m(v^2 - u^2) by putting all the values found.

Delta K.E = 1/2*5*0.4*4.4
= 4.4 Joules

Hope this helps you.
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