CK-12 Foundation
Ck 12: Universal Law of Gravity
[Free Registration/Login may be required to access all resource tools.] In this online tutorial students will learn to describe and calculate how the magnitude of the gravitational force between two objects depends on their masses and...
Khan Academy
Khan Academy: What Is a Centripetal Force?
Learn what centripetal forces are and how to calculate them. Included are two problems with the solutions provided.