It must be noted that the frictional force (f=mu*N) which effects the
linear acceleration should not be assumed to be the same as the frictional
force (F=MU*N) which effects dissipation. It is by VIOLATING this dictum
that one reaches Mike's conclusion (which I would re-word as: the energy
dissipated cannot quantitatively be accounted for as the line integral of
a CONSTANT frictional force).
| ----- Original Message -----
| From: "Edmiston, Mike" <edmiston@BLUFFTON.EDU>
| To: <PHYS-L@lists.nau.edu>
| Sent: Wednesday, October 30, 2002 10:12 AM
| Subject: Re: When Physical Intuition Fails
|
| | Here are a few interesting things I learned from this discussion.
| | . . .
| | (3) Speaking of multiple avenues for energy, I find it interesting
that
| | thermal energy because of mu*N*delta(x) cannot be the only dissipation
| | in this problem. If we assume that slipping dissipation is the only
| | avenue of energy loss from the system, we end up with a final velocity
| | that is slightly higher than the final velocity calculated by
| | conservation of momentum. Thus, this situation not only requires some
| | amount of dissipation (as others have nicely pointed out) it requires
| | more dissipation than simple slipping.
| | . . . I am going a further step and saying that I think we
| | also need another avenue of energy dissipation
| | even if we do have slipping at the tire/road interface.
---
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