• Revision:Newtons laws of motion

TSR Wiki > Study Help > Subjects and Revision > Revision Notes > Mathematics > Newton's Laws of Motion


1st Law

  • An object will remain in a state of rest or in uniform motion in a straight line unless acted on by an external net force.

2nd Law

  • The acceleration of a body, acted upon by an external net force, is directly proportional to the force being applied and inversely proportional to the body's mass.
  • Force = Mass x Acceleration

This can be mathematically notated as: F = ma

If the mass is assumed to be constant, and either the acceleration is an average, or is also constant: F = \frac{m(v-u)}{t}\quad \because\quad a = \frac{v-u}{t}.

For A Level maths and physics the following may also be useful:

The rate of change of momentum of a body is equal to the external net force being acted upon it, acting in the direction of the applied force"

3rd Law

  • If body A exerts a force on body B, body B will simultaneously exert a force of equal magnitude, but opposite direction, on body A


Try Learn together, TSR's study area

revision notes




a study planner

of discussions

What is your favourite film genre?
Study resources

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE