Gravitation and Circular Motion Rapid Review for AP Physics B & C

For a more thorough review, refer to these concepts:

• Gravitation and Circular Motion for AP Physics B & C
• Newton's Law of Gravitation for AP Physics B & C
• Gravitation and Circular Motion: Of Special Interest to Physics C Students

Rapid Review

• When an object travels in a circle, its velocity vector is directed tangent to the circle, and its acceleration vector points toward the center of the circle.
• A centripetal force keeps an object traveling in a circle. The centripetal force is simply whatever net force is directed toward the center of the circle in which the object is traveling.
• Newton's law of gravitation states that the gravitational force between two objects is proportional to the mass of the first object multiplied by the mass of the second. This also means that the gravitation force felt by one object is the same as the force felt by the second object.
• Predictions of Kepler's laws: Planets undergo elliptical orbits with the sun at one focus; at points in an orbit closer to the sun, a planet moves faster; the smaller a planet's mean distance from the sun, the shorter its orbital period, by T² α R³. (The symbol "α" means "is proportional to.")