7.3 Gravitational Potential Energy
Work done against gravity stored as mgh, why only the change in height matters, and picking a reference level that simplifies the algebra.
3 exercises
7.3 Exercise 1
A 1.0 kg baseball is flying at 10 m/s. How much kinetic energy does it have? Potential energy?
- 10 J, 20 J
- 50 J, 20 J
- unknown, 50 J
- 50 J, unknown
7.3 Exercise 3
You have a 120-g yo-yo that you are swinging at 0.9 m/s. How much energy does it have? How high can it get above the lowest point of the swing without your doing any additional work, on Earth? How high could it get on the Moon, where gravity is 1/6 Earth’s?
7.3 Exercise 8
Suppose a 350-g kookaburra (a large kingfisher bird) picks up a 75-g snake and raises it 2.5 m from the ground to a branch. (a) How much work did the bird do on the snake? (b) How much work did it do to raise its own center of mass to the branch?
Adapted from College Physics © 2022 Rice University. Licensed under CC BY 4.0. Sources: College Physics 2e, College Physics for AP® Courses 2e. Imported at revision f98d7a7.