Harold stretches a rubber band and lets it go. The rubber band flies across the room. He says this demonstrates the transformation of kinetic to elastic potential energy. Is Harold correct?

1 Answer
Nov 16, 2015

Harold is not correct, if we assume he is referring only to when he releases the band.

Explanation:

As Harold stretches the rubber band he converts kinetic energy (moving his arm) into elastic potential energy(the stretch of the band). When he releases the band this elastic potential energy is converted into kinetic energy (the band moving).

The question is a bit ambiguous because when he is stretching the band the energy is converted:
#"Kinetic energy" -> "Elastic potential energy"#
So he would be correct while he is stretching the band

But the way I read the question is that it refers to after Harold releases the band. After the band is let go the energy is converted:
#"Elastic potential energy" -> "Kinetic energy"#
So Harold would be incorrect.

Since the question is ambiguous, I think you could say that Harold was either correct or incorrect, and you would not be wrong if you explained and justified your answer. When Harold stretches the band he is correct, but after he releases the band he is incorrect. Make the choice that you think is most correct and ensure you justify your answer.