Let h = 25.5 m and vi = 13.6 m/s. Find the speed of the ball just before it hits the ground. vf = 26.167919 m/s Find the ball's mechanical energy at the release point. KEi + PEi = _______J Find the ball's mechanical energy just before it hits the ground. KEf + PEf = ________J Calculate the mechanical energy and final speed of a 0.9 kg ball tossed at 17.3 m/s from the top of a 45.2 m high building. KE + PE = __________J vf=___________ m/s