Question

Two clay balls are moving towards each other along a common

straight line. The one on the left has mass 2 kg and velocity 2 m/s.

The one on the right has mass 1 kg and velocity 7 m/s. The balls

collide and form a single ball of mass 3 kg and keep moving. Some

kinetic energy is lost as heat in this process. The lost energy in the

process is · · ·. Expressanswer in Joule

Answer 1

Since the collision is perfectly inelastic, the net linear momentum will be conserved.

So M1V1+M2V2=(M1+M2)V
Or (7)(1) + (2)(-2)=(3)V
Or V=1m/s

So, loss in kinetic energy=1/2M1(V1)^2 + 1/2M2(V2)^2 - [1/2(M1+M2)V^2]
= 1/2(1)(7^2) + 1/2(2)(2^2) - 1/2(3)(1^2)
=49/2 + 4 - 3/2
=27J