Newton’s Second Law

Newton’s second law can be shown as the equation:

  • F = Resultant force in newtons (N)
  • m = Mass in kilograms (kg)
  • a = Acceleration in metres per second squared (m/s2)

This equation can also be rearranged, to form:

Based on the equation, the acceleration of an object is determined by two main factors:

  • Directly proportional to the resultant force acting on it – As the resultant force increases, so does the acceleration.
  • Inversely proportional to its mass – For a given force, if the object’s mass increases, its acceleration decreases.

Inertial Mass

Inertial mass measures an object’s resistance to changes in its velocity. We can calculate this by rearranging the equation from Newton’s second law, to form:

Therefore, inertial mass represents the ratio of force to acceleration.

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