When a resultant force (that is not zero) acts on a stationary or moving object, the object changes velocity. When the velocity changes, so does the momentum.
To calculate the force acting on an object, we multiply the mass of the object by its acceleration. This is represented by the equation:
Force = Mass × Acceleration
To calculate the acceleration, we divide the change in velocity by the time taken (change in time):
Acceleration = Change in velocity / Time taken
We can combine the two equations to form:
Force = (Mass × Change in velocity) / Time taken
The mass multiplied by the change in velocity is another way of saying the change in momentum. So:
Force = Change in momentum / Time taken
You can also say that Force = the rate of change in momentum
A man and a woman are in a car travelling at 25 m/s.
If the car comes to a stop in one second:
a) Calculate the forces acting on the man
b) Calculate the forces acting on the woman