Re: Student question??

[Richard Tarara <rtarara@SAINTMARYS.EDU>]

----- Original Message -----
From: "Michael Burns-Kaurin" <mburns-k@SPELMAN.EDU>

> Maybe the difference occurs when the ball hits the court.
>
> Michael Burns-Kaurin
>
> Cliff Parker wrote:
> > A student posed a question to me yesterday that I am not
> > sure I have a complete handle on.  Perhaps some of you can
> > help.  He is a tennis player and was wondering why a ball
> > hit with top spin bounces higher than a ball sliced over the
> > net with backspin.  The ideas that came to my mind had to do
> > with Bernoulli causing the path of the ball to change and
> > therefore causing the vertical component of the balls
> > velocity and therefor the vertical component of the kinetic
> > energy to increase.  I am not convinced that there is not
> > something significant I am not thinking of.  Any guidance
> > would be appreciated.

I would think that the effect of the spin on the ball WOULD show itself
primarily in the ground/ball interaction.  However, I question the
observation.  Tennis buffs can confirm or refute, but from the couple of
times I actually played someone 'good' (and then quickly gave up the game
;-) it seemed to me that balls with top-spin shot forward and much lower
than my kind of 'neutral' stroke.  It's been a while, but mostly I remember
watching lots of those balls go by me--fast and low.

Rick

(In my game, golf, backspin will cause the ball to rise and top spin (harder
to impart) will keep the ball low, but the balls are specifically designed
to take advantage of these aerodynamic effect.  A golf ball without the
'dimples' cannot be hit much more than 100 yards.)