Newton's Laws of Motion

During his life Issac Newton formulated many theories and discovered many things that affect our everyday lives. In practice we are unaware of these various scientific phenomena, but there are times when we actively need to analyse a problem governed by these rules. Among the many things that Newton discovered are his three laws of motion. As presented here they are applicable to linear motion, but they can equally as well be applied to systems with rotational dynamics.

Newton's First Law of Motion

A body will remain at rest or continue to move in a straight line at constant speed unless acted upon by an external force.

Newton's Second Law of Motion

The sum of all the external forces acting upon a body will cause it to accelerate at a constant rate proportional to the magnitude of the total force and the mass of the body. This is summarized by the equation:

F = ma

Newton's Third Law of Motion

When a force is exerted on a body the body will exert a corresponding force of equal magnitude in the opposite direction. This is often summarized as:

Action and reaction are equal and opposite