Objectives

At the end of this section you should be able to:

1. define momentum and impulse
2. state principles of conservation of linear momentum
3. solve problems involving change and conservation of momentum

The impulse of a constant force F is defined as the product of the force and the time t for which it acts.

The effect of the impulse on a body can be found using Equation 1.1, where a is acceleration, u and v are initial and final velocities respectively and t is time.

So

Impulse is a vector quantity and has the sane units as momentum, Ns or kg m/s

The impulse of a variable force can be defined by the integral

where t is the time for which F acts.

By Newton's 2^nd law

So impulse can also be written

Which for a constant mass

In summary