- We know how to calculate the
**kinetic energy**of moving objects -- isn't that enough? No. It turns out that many situations involving**collisions**do not obey the simple conservation of Mechanical Energy. Why not? Because it takes energy to bend, break, mutilate and deform objects, energy which disappears from the kinetic and gravitational potential energy. - But a different quantity
*is conserved,*even during collisions. The**linear momentum**of an object is defined asp = (mass) * (velocity)

It is a vector quantity, and the total linear momentum of a bunch of objects will remain the same, before and after a collision. - Momentum is connected to force by
**impulse**:impulse = (force) * (time)

- The Momentum-Impulse Theorem states that in order to change
the momentum of an object, one must exert an impulse
(change in momentum) = (impulse) p - p = (force) * (time) final initial m*v - m*v = (force) * (time) final initial

Copyright © Michael Richmond. This work is licensed under a Creative Commons License.