Khan Academy
Khan Academy: The Buoyant Force Does Not Get Smaller as You Sink
This article explains the buoyant force using a submarine as an example. It also discusses what determines the size of the buoyant force using a formula, and explains decompression sickness better known as the bends.
Georgia Department of Education
Ga Virtual Learning: Physical Science: Force and Motion
In this student-paced module, students apply Newton's Laws of Motion to everyday life, calculate mathematical relationships involving force and motion using algebraic formulas, and understand the difference between mass and weight.
Wikimedia
Wikipedia: Centripetal Force
Wikipedia's site on centripetal force provides a section explaining the difference between centripetal force and centrifugal force. Includes formulas and hyperlinked terms.