# Newton's Laws of Motion

Sir Isaac Newton published *Philosophiae Naturalis Principia Mathematica* in 1687. This text contains the three basic laws on which mechanics is based

- Every body continues in its state of rest or of uniform motion in a straight line unless acted on by some external force.

- No force = no acceleration

**Newton's First Law**

- The rate of change of momentum of a body is directly proportional to the external force acting on the body and takes place in the direction of the force.

- where
*F*= force acting on the body [N]*m*= mass of the body [kg]*v*= velocity of the body [ms^{-1}]

- the rate of change of velocity is the acceleration
- where
*a*= acceleration of the body [ms^{-2}]

**Newton's Second Law**

- If a body
**A**exerts a force on body**B**, then**B**exerts an equal and oppositely directed force on**A**.

- Weight is the magnitude of the force of gravity.

**Newton's Third Law**

**See also: **Equations of Motion, Inertial Reference System, Keplers Laws, Newton, Isaac, Newtonian Mechanics, Noninertial Reference System, Special Theory of Relativity.

**Subjects: ** Physics

- Newtons Castle A stimulating journey into the revelations of Sir Isaac Newton. Learn about his discovery of Gravity and Optical Theories.

**Weblinks:**