Question

1. describe the changes in ke and pe of a person jumping up and down on a trampoline.

a. while going up, the person’s ke would change to pe. while coming down, the person’s pe would change to ke.
b. while going up, the person’s pe would change to ke. while coming down, the person’s ke would change to pe.
c. while going up, the person’s ke would not change, but while coming down, the person’s pe would change to ke.
d. while going up, the person’s pe would change to ke, but while coming down, the person’s ke would not change.

Explanation:

To solve this, we recall the definitions of kinetic energy (KE) and potential energy (PE). KE is energy of motion, PE (gravitational here) is energy due to height. When going up: speed decreases (KE decreases), height increases (PE increases) → KE converts to PE. When coming down: height decreases (PE decreases), speed increases (KE increases) → PE converts to KE. Option a matches this. Option b reverses the conversions. Option c says KE doesn't change when going up (false, speed drops). Option d says KE doesn't change when coming down (false, speed increases).

Answer:

a. While going up, the person’s KE would change to PE. While coming down, the person’s PE would change to KE.