Question

Determine the amount of potential energy of a 5N book that is moved from the ground to three different shelves in a bookcase. The height of each shelf is 1m, 1.5m and 2m from the ground.

Answer 1

$PE=mgh$

When the book is on ground,$mgh=0J$

When it is taken to first shelf :$mgh=5\times 1=5J$

When it is taken to second shelf :$mgh=5\times 1.5=7.5J$

When it is taken to third shelf :$mgh=5\times 2=10J$