Re: When Physical Intuition Fails

[John Mallinckrodt <ajm@CSUPOMONA.EDU>]

Michael Edmiston wrote:

> Since John's power calculation gives a correct result by the usual
> friction force of mu*normal-force, I presume mu*m*g*(R*delta-theta -
> delta-x) ought to work for calculating the dissipation without
> having to do a power calculation.  My problem is that I have worked
> through the algebra a couple times and it didn't come out right.  In
> fact, I didn't get the same result the two times I tried it, and at
> this point I have put off grading my lab reports long enough..

It'll be a simple error.  This clearly works since integrating the
velocities is the same thing as integrating the rate of dissipation
divided by the constant frictional force.  Subsequently multiplying
the result by the frictional force then returns the same answer.

(... and congratulations for evidently getting to the bottom of the
"=" signs in your email.  Now you've just got to figure out how to
get rid of those hard line breaks at 132 characters!)

--
John Mallinckrodt        mailto:ajm@csupomona.edu
Cal Poly Pomona          http://www.csupomona.edu/~ajm

This posting is the position of the writer, not that of SUNY-BSC, NAU or the AAPT.