Angular Momentum Earlier we defined the angular momentum for rotation about a fixed axis as

L = I

Now we will investigate angular momentum in more detain -- for more general cases.

The angular momentum

Lof aparticleis defined as

L=rxpThe particle is located at position

r(relative tosome origin -- so this means our angular momentumLis definedrelative tothat origin as well).pis thelinear momentumof the particle.We can start with our basic definition of torque,

If there are several forces acting on one particle, we can sum these forces and their associated torques,

What is this

rx (^{d}/^{p}_{dt}) term?

This means that if the

net torque is zero, the angular momentum isconserved.

L_{final}=L_{initial}For a rigid body (and that is all we will consider) we can also write the

angular momentumas

L= Ior

This means

angular momentumis a vector that points in thesame directionas theangular velocity.

TorqueConservation of Angular MomentumReturn to ToC, Ch11, Rolling Motion(c) Doug Davis, 2001; all rights reserved