What happens to kinetic energy in a car collision?

[RachelT]

first post so here goes: this question isn't hard but i can't seem to get the answer i should have.

'a car of mass 1050kg runs into the back of car b which is stationary with mass 1200kg. car A was moving at 50mph immediately before impact. after impact, the vehicles are locked together'

calculate the speed at which the 2 vehicles move immediately after collision and the amount of kinetic energy lost in the collision. what has happened to this energy?

any help appreciated. thank you!

 

[CWatters]

Welcome to the forum. You are meant to show your attempt at a solution and any equations/assumptions used before asking for help.

 

[Simon Bridge]

Duplicate:
https://www.physicsforums.com/showthread.php?t=627246
... there's more discussion there.