A 1000kg compact car is travelling north at 15m/s when it collides with a truck travelling east at 10m/s. All occupants are wearing seat belts and there are no injuries, but the two vehicles are thoroughly tangled and move away from the impact point as one mass. The insurance adjustor has asked you to find the velocity of the wreckage just after the impact. What do you tell her?

2 answers

momentum is conserved ... but you need the mass of the truck to give an exact answer
useful