Newton's laws of motion are summarized below.

Newton's Laws of Motion Summary

Newton's First Law of Motion

An object remains at rest (if originally at rest) or moves in a straight line with constant velocity if the net force on it is zero.

Newton's Second Law of Motion

A particle with a force acting on it has an acceleration proportional to the magnitude of the force and in the direction of that force.

Newton's Third Law of Motion

The forces of action and reaction between interacting bodies are equal in magnitude and opposite in direction.

- or -

For every action there is an equal and opposite reaction.

Newton's Universal Law of Gravitation

Each and every mass in the universe exerts a mutual, attractive gravitational force on every other mass in the universe. For any two masses, the force is directly proportional to the product of the two masses and is inversely proportional to the square of the distance between them.