Impulse and Momentum. The principles of linear and angular
impulse and momentum are used to solve problems involving force,
velocity, and time. Before applying the equations, draw a free-body
diagram in order to identify all the forces which cause linear and angular
impulses on the body. Also, establish the directions of the velocity of the
mass center and the angular velocity of the body just before and just after
the impulses are applied. (As an alternative procedure, the impulse and
momentum diagrams may accompany the solution in order to graphically
account for the terms in the equations. These diagrams are particularly
advantageous when computing the angular impulses and angular
momenta about a point other than the body's mass center.)