A .75 kg mass moving with a speed of 5.0 m/s encounters a .25 kg mass moving in the opposite direction with speed 5.0 m/s.
I) Assume the two objects collide and stick together. What is the velocity of the combined mass after the collision?
II) Assume the objects collide in an elastic collision where no energy is lost. What is the final velocity of both objects?
Please answer in specific details and description.