A ball is shot directly upward from the ground with an initial speed of v0 = 7.40 m/s.

A ball is shot directly upward from the ground with an initial speed of v0 = 7.40 m/s. Simultaneously, a construction elevator cab begins to move upward from the ground with a constant speed of vc = 2.40 m/s. What maximum height does the ball reach relative to (a) the ground and (b) the cab floor? At what rate does the speed of the ball change relative to (c) the ground and (d) the cab floor? (Give the magnitude of the rate of change)