# Maximum possible momentum change in isolated system

1. Feb 15, 2006

### xailer

hello. If in isolated system two objects (one wih momentum 6 and the other with momentum 3)collide, total momentum of the system always remains the same (total_momentum=9).

Depending on the mass, material of objects and some other variables, the change of momentum could vary. Does maximum possible change of momentum equal (for this example) 6? Does it have something to do with kinetic energy? Else why couldn't change of momentum be some larger value,like 10^4? Total momentum would still be the same!

How do we find with help of kinetic energy formula, maximum possible change of momentum in an isolated system?

thank you

2. Feb 15, 2006

### durt

The total kinetic energy after the collision must be less than or equal to the energy before. This is true unless the two objects "push off" each other, providing more energy (from inside of them, like energy in your muscles). In this case, the velocities and the differences in momentum can be arbitrarily large.

3. Feb 16, 2006

### xailer

This "push off" doesn't happen when ordinary objects like balls or rocks... collide?

How do we find with help of kinetic energy formula, maximum possible change of momentum in an isolated system?