> > the rebound speed would be the same as the inbound speed no matter > > how long the collision took. > > Even if someone is swinging the racket (which is highly likely)?
I was thinking of the case of an incompetent player (such as myself) who is just going to hold the racket up to the ball. Of course if you swing, it you will impart some kinetic energy to the ball and it will come off faster. But the dynamics of the collision are still mostly determined by the squishiness of the ball and the stretchiness of the racket stringing. To the extent that they are both elastic (don't turn some of the energy into heat by internal friction) it doesn't affect the return speed of the ball. > or is there really some > substance we're likely to find on a tennis racket that will keep > contact with the ball longer yet send it back faster? After all, > we're discussing the difference between nylon and gut here. No substance involved. Noting is "sticking" the ball to the racket - the ball and strings act like springs: they take time to stretch out and then return to the original shape. The stretchier and squishier, the longer this takes. A stretchier stringing (weaker spring constant) will take longer to slow the ball down and accelerate it back in the other direction but it won't affect the return speed. (Again, assuming it is mostly elastic which means it eventually returns the energy to the ball.) Try imagining a racket strung with ordinary rubber bands - it might give you a mental picture of what is going on. ...Bob -- To get on or off this list see list information at http://www.cs.dartmouth.edu/~wbc/lute-admin/index.html
