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Angular Momentum

Let's define the angular momentum for a point object similar to the way we did it for the torque


If this is really analogous, the first thing we should check is if the analogy to tex2html_wrap_inline776 holds:


Here we used the fact that the cross product of a vector with itself is zero.

So it does seem like this definition of tex2html_wrap_inline778 makes sense from a mathematical point of view. If we have many forces acting on the system, it is straightforward to extend this so that in general


For a continuous object let's look at the two dimensional case considered above where we showed that tex2html_wrap_inline748 , where tex2html_wrap_inline730 points perpendicular to the rotating object. Since I is constant in time this says that




(note that if tex2html_wrap_inline784 all velocities are zero so tex2html_wrap_inline786 ).

Joshua Deutsch
Sun Feb 23 15:54:50 PST 1997