What is the Explanation for Inelastic Collisions in Physics?

[omkhan95]

Hi everyone,

I am a student of A'Levels and I am having a problem with a Question regarding inelastic collision the question is as follows:

Whenever two bodies collide and they stick together the collision is essentially inelastic. Explain?

Can anybody help me out with this this is a challenge from my physics teacher...I tried it but no good so please help me out...:) following is my answer which my teacher said is not correct...

 

[Andrew Mason]

Analyze the collision in the frame of reference of the centre of mass of the two colliding objects. What is the kinetic energy before the collision? What is it after?

AM