Relativistic inelastic collisions

[Amith2006]

1. The problem statement, all variables and given/known data
1) Two identical bodies, each with rest mass m(o), approach each other with equal velocities u, collide and stick together in a perfectly inelastic collision. Determine the rest mass of the composite body.


2. Relevant equations



3. The attempt at a solution

The solution as given in my book is:
Let M(o) be the rest mass of the composite body.
E(initial)=E(final)
[2m(o)c^2]/{[1 - u^2/c^2]^(1/2)} = M(o)c^2
Unlike non relativistic perfectly inelastic collisions, is Total energy conserved in perfectly inelastic relativistic collisions?

[Saketh]

Unlike non relativistic perfectly inelastic collisions, is Total energy conserved in perfectly inelastic relativistic collisions?
Total energy and kinetic energy are different things. Kinetic energy is not conserved in inelastic collisions, while total energy is always conserved, regardless of whether or not we take relativistic events into account. (In an inelastic collision, energy is conserved because kinetic energy is transferred into heat/sound, etc.)

[Amith2006]

Thats cool! Thanx.