Question

A stationary mass explodes into two parts of mass 4 Kg and 40 Kg. If the initial kinetic energy of larger
mass is 10 J, find the velocity of smaller mass?

Answer 1

Use conservation of momentum:

Mv1+mv2 =0

So: v2 =-Mv1/m =-10v1

v1 =sqrt(2*10/40)=sqrt(1/2) =0.71 m/s

Hence v2 =-10v1 =-7.1 m/s

The velocity of the smaller mass is 7.1 m/s in the opposite direction.