Question

Two objects move on a horizontal frictionless surface along the same line in the same direction which we shall refer to as foward direction. The trailing object of mass 2.0kg has a velocity of 15m/s foward. The leading object of mass 3.2 kg has avelocity of 11m/s foward. The trailing object catces up with the leading object and the two objects exprience a completely inelastic collision. what is the final velocity of the two objects