8. Professor Lewin releases the ball from his waist (h = 1.2m). a) If he ensures that the ball has zero motion when released from position A, what would be the ball's velocity at its lowest point? Show all work starting with Ebefore = Eafter. b) How high would the ball go on the other side (assuming no energy lost to heat)? c) Since it WILL lose a tiny bit of energy, what do you know about the maximum heights each swing? d) How can professor Lewin be so confident that he won't be going to the hospital? e) Why was he SO careful about how he released the ball? 9. A girl runs at top speed (6.5 m/s) and grasps a 5.0 m rope hanging vertically from a tall tree at the edge of a lake. Show all work starting with Ebefore = Eafter. a) how high can she swing upward? b) does her mass affect the answer? How do you know