a car of mass 2100 kg collides with a motorcycle of mass 290 kg. after the collision, the car and motorcycle stick and slide together. the car's velocity just before the collision was , and that of the motorcycle was . determine the velocity of the stuck-together car and motorcycle just after the collision. < . . 27.57 unanswered , . . -7.57 unanswered > . . . . determine the change in internal energy of the car and motorcycle (thermal and deformation).