15+Forces+and+Motion

=Chapter 15= =Forces and Motion=

**You learned...**

 * ====Forces acting on objects can be identified.====
 * ====Total forces acting on an object determine the effect of the forces.====
 * ====Friction is both helpful and harmful.====
 * ====Mass and distance affect the gravitational forces between objects.====
 * ====Gravity affects Earth's tides and planetary movement.====
 * ====Frame of reference is used to describe motion.====
 * ====Speed, velocity, and acceleration are related.====
 * ====Gravitational force affects objects.====
 * ====Newton's three laws can be explained with examples proving the law.====