6. In a non-injury chain-reaction accident, on a foggy freeway, car 1 (mass of 2000
kg) moving at 15.0 m/s to the right elastically collides with car 2, initially at rest.
The mass of car 2 is 1500 kg. In turn, car 2 then goes on to lock bumpers (that is,
it is a completely inelastic collision with car 3, which has a mass of 2500 kg and
was also at rest. Determine the speed of all cars (i.e., car 1, car 2, and the car 2/3
combo) immediately after this unfortunate accident.
