Question

Alana summarized what happens when a ball sitting on top of a grassy hill rolls down the hill.

The motionless ball has potential energy. Once the ball starts to roll down the hill, new kinetic energy is made. As the ball rolls across the grass, it slows down. The kinetic energy of the ball is converted to other forms of energy.

Which best describes Alana’s error?

Kinetic energy is not made; it is a result of energy transformation.
The ball cannot slow down unless someone touches it.

Answer 1

"Kinetic energy is not made; it is a result of energy transformation."

Explanation: the ball's gravitational potential energy is converted into kinetic energy as it rolls downhill — energy is transformed, not created. The ball can slow down because forces like friction and air resistance convert its kinetic energy into thermal energy and sound, without anyone touching it.