This document discusses Newton's three laws of motion: 1) Newton's first law states that objects at rest will stay at rest and objects in motion will stay in motion unless acted on by an unbalanced force. Gravity and friction are common unbalanced forces. 2) Newton's second law relates the acceleration of an object to the net force acting on it and its mass. It is expressed by the equation F=ma, where F is force, m is mass, and a is acceleration. 3) Newton's third law states that for every action there is an equal and opposite reaction. When one object exerts a force on a second object, the second object exerts a force back on the first object