A ball, starting from the rest position 1, rolls down and then up a curved track towards position 5. The ball speeds up as it rolls from position 1 position 3, and it slows down as it rolls from position 3 to position 5. When it reaches position 5, it rolls back down the track. At which point is gravitational potential energy being transformed into kinetic energy? A. Only when the ball rolls from position 1 to position 3.
B. Only when the ball rolls from position 3 to position 5.
C. When the ball rolls from position 1 to 3 and from position 5 to 3.
D. The entire time the ball is rolling from position 1 to position 5.