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Re: MOMENT OF INERTIA



By giving them the same speed, you are giving more total kinetic energy
to the object with the larger moment of inertia.

Bob Sciamanda
Physics, Edinboro Univ of PA (ret)
trebor@velocity.net
http://www.velocity.net/~trebor
-----Original Message-----
From: Ludwik Kowalski <kowalskiL@MAIL.MONTCLAIR.EDU>
To: PHYS-L@LISTS.NAU.EDU <PHYS-L@LISTS.NAU.EDU>
Date: Friday, December 18, 1998 11:38 AM
Subject: Re: MOMENT OF INERTIA


Brian Whatcott wrote:

... The next step is to consider letting both of them run along
the flat floor at the foot of the ramp.
Which is likely to travel further, I wonder?

Thanks for providing an excuse for breaking the monotony of
grading. We have two solid cylinders which have the same shape,
the same weight (0.95 Lb) and the moments if inertia which differ
by a significant factor (perhaps 2 or 3).

Rolling them down along the inclined plane (about 20 degrees)
I see that the cylinder whose moment of inertia is smaller gains
linear speed at a higher rate. Then I placed them on the horizontal
floor (linoleum, not very clean) and pushed them at the same time
with a ruler. The initial speeds are about the same, perhaps 1
or 2 m/s. The cylinder whose moment of inertia is larger
covers about 5 m before stopping while for the other cylinder
the distance traveled is about 4 m. I did this 5 times. Nothing
but the weights was measured; all numbers come from rough
estimates.

Somebody may wish to play with this via simulations. Interactive
Physics is ideal for this because you can control the "air resistance".
The initial conditions can also be controlled better than I was
doing with my pusher. Please share the results.

Ludwik Kowalski