Question

A man holds a book near a bookcase at the level of bookshelf B. Bookshelf A is above B. Bookshelf C is below B.
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
stays the same

shelf B
increases

shelf C
decreases

Answer 1

Your answers are mixed up. Correct choices:

- shelf A: increases
- shelf B: stays the same
- shelf C: decreases

Reason: gravitational potential energy U = mgh. Mass m and g are constant, so U changes only with height h. A is above the current height → h increases → U increases. B is the same height → U unchanged. C is below → h decreases → U decreases.