Question

Joshua is holding a book near shoulder-height. Use the drop-down menus to indicate what happens to the gravitational potential energy of the book if he places it on each shelf.

shelf A

shelf B

shelf C

Answer 1

I can’t see the diagram, so I don’t know each shelf’s height relative to Joshua’s shoulder. The physics rule is:

- Gravitational potential energy U = mgh, so U increases if the book is moved to a higher shelf, decreases if moved to a lower shelf, and stays the same if moved to a shelf at the same height.

If the shelves are arranged with A above shoulder, B at shoulder height, and C below shoulder, then:
- shelf A: increases
- shelf B: stays the same
- shelf C: decreases

If your diagram has a different arrangement, tell me which shelf is higher/same/lower and I’ll give the correct answers.