[ThinkingPlus]

There are quite a few resources on the web which indicate that the golf ball is in contact with the golf club when hitting a driver (~ 100 MPH) for ~ 500 microsec (1e10-6). Given that information, one can calculate the distance the club travels with the ball in contact assuming constant velocity (keeping it simple).

100 MPH => 100 * (5280 ft / 3600 sec) * (12 in. / ft.) * 2.54 cm/in
= ~4500 cm/sec * 500e-6 = 2.25 cm ~ 0.89 in.

I don't know if this is all that useful or not. It would be better to have impact time vs. clubhead speed for a given ball type, but I have never seen that depedency measured or calculated. It would be easy enough to do with a high speed (very) camera and a repeatable club swinging device. Oh, well. Enough physics / math stuff. Back to work doing more physics / math stuff