Re: Conservation of angular momentum

On 2007-06-01, Peter <Poakfield@xxxxxxx> wrote:
On May 31, 5:59 pm, "Greg Neill" <gneill...@xxxxxxxxxxxxxxx> wrote:
"Ben C" <spams...@xxxxxxxxx> wrote in message

news:slrnf5udes.t9o.spamspam@xxxxxxxxxxxxxxxxxxxx

On 2007-05-31, Greg Neill <gneill...@xxxxxxxxxxxxxxx> wrote:
If your ball is stopping despite your lever massing <3x that
of the ball I'd start looking for frictional losses.

You mean >3x. Peter says his lever weighs 6x what the ball does.

Oops. My bad. Yes, I should have said >3x.



When the ball strikes the lever there's going to be a short term high
lateral force on any pivot. There will be acoustic losses in the
lever as it vibrates, too. Have you calculated the vibration modes of
the lever?

Of course there must be energy losses somewhere. I don't draw the
conclusion that energy (orangularor linearmomentum) is not conserved!

Acoustic losses are probably not very high since generally speaking it
takes very little power to make a lot of noise. But I don't know the
actual masses and sizes involved so I don't know how much energy we're
talking about.

By acoustical I meant to imply vibration modes in the
lever with stress/strain frictional losses in addition
to any tiny sound emissions.

If the lever arm is made of a material with significant
flexure, it could dissipate a lot of energy via vibration.
If it's thick enough to prevent these vibrations to a large
degree, we should take a closer look at the assumption that
its moment of inertia is that of the classic "thin rod".
Actual dimensions and composition would be helpful.

The lever consists of a steel rod of 1/4 x 1/4 x 12 inches, with a
mass of about 100 grams.

How fast is the ball moving when it hits the rod?
.

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  • Re: Conservation of angular momentum
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  • Re: Conservation of angular momentum
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