Force (Also seen in GCSE Physics 2)

If we start at F = ma we can derive an equation that links force and momentum.

we can replace a in this equation with from Unit 2

multiplying out makes the equation

or where ∆ means ‘the change in’

This states that the force is a measure of change of momentum with respect to time. This is Newton’s Second Law of Motion:

The rate of change of an object’s linear momentum is directly proportional to the resultant external force. The change in the momentum takes place in the direction of the force.

If we have a trolley and we increase its velocity from rest to 3m/s in 10 seconds, we know that it takes a bigger force to do the same with a trolley that’s full of shopping. Ever tried turning a trolley around a corner when empty and then when full?

Force is measured in Newtons, N