Practice!

Sample Problem

Sally lifts a book 2.2 meters from the floor to the top of her bookshelf. If the book has a mass of 1.3 kg, what is the gravitational potential energy gained by the book? Estimate g to be 9.8 m/s2.

Joules

Solution

Use the formula Ug = mgh, so if you plug in the known values, you get Ug = (1.3) (9.8) (2.2) = 28.028 J.