Science Assessment

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.  The ball starts from rest at the position labeled Start and goes down and then up the track toward the right.

What is the highest position the ball will reach before stopping and going back down the track?  Why?  (Remember that no energy is transferred between the ball and the track or between the ball and the air around it.)

1. Position 1.  As the ball goes down one side, its gravitational potential energy will decrease, and its kinetic energy (motion energy) will increase, but its kinetic energy will not increase enough for it to go past Position 1.
2. Position 2.  As the ball goes down one side, its gravitational potential energy will change into kinetic energy (motion energy), and as the ball goes up the other side, its kinetic energy will be changed back into the same amount of gravitational potential energy it started with.
3. Position 3.  As the ball goes down one side, its kinetic energy (motion energy) will be added to its gravitational potential energy, which gives it enough energy to go higher than it started.
4. The position the ball will reach depends on how much the ball weighs because gravitational potential energy and kinetic energy (motion energy) both depend on the mass of the ball.