 # Average Force Formula

## Average Force

The force applied by a body that’s travelling at a definite velocity (rate of speed) for a definite period of time is the average force. Force is a vector quantity that has both magnitude and direction. The word ‘average’ is made use of to specify that this velocity is not an accurately measured or ‘instantaneous’  velocity. Therefore, the mass of the body multiplied by the average velocity over the definite time is equivalent to average force. Average force is a vector quantity that has both magnitude and direction.

For a particular interval of time t, the force is described as the frequency of change of momentum. It is hard to compute the rate of change if the time interval is minor. There the term, average force makes an entrance.

Over a period of intervals (Δ t) the rate of change of momentum is Average Force. It is given by

F = m (vf – vi)/Δ t

Where,
the mass of the body is m,
the final momentum is vf,
the initial momentum is vi,
the change in time is Δ t.

The Average Force Formula aids one in getting the rate of change of momentum for any number of time intervals  (Δ t). Expressed in Newton (N).

### Solved Examples

Example 1: A child throws bowling ball having a mass of 5 kg and it rolls with a velocity of 4 m/s for 1 s. Compute its average force?

Known: Mass of bowling ball m = 5 kg,
Initial velocity vi = 0
Final velocity vf = 4 m/s

The Average force is given by

F = m (vf – vi)/Δ t

F = 5 (4-0)/1

F= 20 N

Example 2: A rubber ball of mass 0.25 kg rolls over the gravel with velocity 1.5 m/s and halts after 2 s. Compute its average force?