H Momentum


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When a particle with mass m moves with velocity v, we define its momentum p, as

p = mv

Momentum is
a Vector

 The total momentum of a system is constant whenever the vector sum of the external forces on the system is zero. In particular, the total momentum of an isolated system is constant.
Conservation of Momentum
is true in all dimensions
Elastic and Inelastic Collisions
Momentum is always conserved.

Kinetic Energy is not necessarily conserved in all collisions.

An Inelastic Collision - Animation

The Ballistic Pendulum
click on the diagram to the right

The time that the Force is applied. . . an important approximation
An applied force acting on a particle may vary in time.

The impulse imparted to the particle by the applied force is the area under the curve.

In the time interval t, the time-averaged force gives the same impulse to the particle as does the time varying applied force.
How does the time of the collision relate to the Force of the collision?