One object is at rest, and another is moving. The two collide in a one-dimensional, completely inelastic collision. In other words, they stick together after the collision and move off with a common velocity. Momentum is conserved. The speed of the object that is moving initially is 21 m/s. The masses of the two objects are 3.6 and 7.5 kg. Determine the final speed of the two-object system after the collision for the case
(a) when the large-mass object is the one moving initially and the case
(b) when the small-mass object is the one moving initially.