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! Edit: I had an answer of 18.65ms-1 for the speed of the coalesced vehicles. My KE lost was 132559.3J.