A boy tosses a ball in the vertical direction off the side of a cliff. if the initial velcoity of the ball is 15 m/s upward, and the ball is released 40m from the bottom of the cliff, determine the maximum height sb reached by the ball and the speed of the ball just before it hits the ground. during the entire time the ball is motion, it is subjected to a constant downward acceleration of 9.81 m/s^2 due to gravity neglect the effect of air resistance.