Re: Conservation of angular momentum

On May 27, 4:36 pm, Sam Wormley <sworml...@xxxxxxxxx> wrote:
Peter wrote:
If a point object collides with an arm of an equal-arm lever and
stops on impact, it transfers all its momentum to the lever. If an arm
of a rotating equal-arm lever collides with a point object and stops
on impact, it transfers all its momentum to the point object. If
angular momentum were r x p, there are many cases where this would be
impossible to happen (I have specific examples, if you want to hear
about them).

That's not right Peter.

Momentum
http://scienceworld.wolfram.com/physics/Momentum.html

Momentum is a conserved quantity, meaning that the total momentum
of any closed system (one not affected by external forces, and
whose internal forces are not dissipative in nature) cannot be
changed.

Angular Momentum
http://scienceworld.wolfram.com/physics/AngularMomentum.html

The total amount of angular momentum does not change with time no
matter how the objects interact with one another.

I absolutely agree that the magnitude of the linear/angular momentum,
m|v|, of an object is conserved if no net external force in the
direction of its motion acts on it. While, necessarily, the direction
of motion of an object in rectilinear motion does not change, the
direction of motion of an object in curvilinear (angular) motion
changes continuously. I have clear experimental evidence that shows
this is true, and that the conservation of "angular momentum " r x p
is not compatible with the conservation of m|v|.

Peter

.

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