Re: squash ball question

[Ludwik Kowalski <KowalskiL@MAIL.MONTCLAIR.EDU>]

The "internal friction" is even more complicated than sliding friction
because textbooks do not provide a model, as far as I know. How
would a cylinder with a bouncing steel spring attached behave at
different temperature? It would probably not bounce very well at a
temperature which is only 100 K below the melting point. Does his
rubber ball bounces better when it is cold? I suppose the floor
temperature is about the same (thinking about asphalt or tiles).
Ludwik Kowalski

Mark Sylvester wrote:

> I have a student doing a project on squash balls: these are rather soft
> rubber balls which don't bounce very well, but get more and more elastic as
> their temperature is raised through being slammed around the court.
>
> He's measuring the coefft of restitution at different temperatures, and
> getting something like a linear graph. The problem is to produce an
> explanation. He needs to be pointed in a fruitful direction, but I find
> myself stuck. It seems clear that it's the air inside the ball that causes
> this behaviour, rather than the rubber, but how to relate this to the
> dissipation that occurs during a bounce...?
>
> I'd appreciate any ideas.
>
> Mark