Item NG094002: Assuming no energy transfer between a ball and the track it is moving in, the amount of energy the ball has after it goes over a hill will be the same as before it went over the hill because the total amount of energy in the system did not change.

Imagine a ball on a track where no energy is transferred between the ball and the track or between the ball and the air around it.  It is going fast enough at Position 1 so that it will go over a hill on the track and past Position 2.  Position 1 and Position 2 are at the same height.

Will the total amount of energy the ball has at Position 2 be more, less, or the same as the total amount of energy the ball had at Position 1 and why?  (Remember that no energy is transferred between the ball and the track or between the ball and the air around it.)

  1. The total amount of energy the ball has will be more at Position 2 because new energy was made when the ball went down the steep side of the hill.
  2. The total amount of energy the ball has will be less at Position 2 because energy was used up when the ball went up the long side of the hill.
  3. The total amount of energy the ball has will be the same at Position 1 and Position 2 because the total amount of energy in the system (ball and track) did not change.
  4. Whether the total amount of energy of the ball is more, less, or the same at Position 2 compared to Position 1 depends on the speed of the ball before it got to the hill.