posted by kay .
An elevator without a ceiling is ascending with a constant speed of 9.7 m/s. A boy on the elevator shoots a ball directly upward, from a height of 2.0 m above the elevator floor, just as the elevator floor is 25 m above the ground. The initial speed of the ball with respect to the elevator is 17.8 m/s. (a) What maximum height above the ground does the ball reach? (b) How long does the ball take to return to the elevator floor?