[hcw]

DG,

Glad you could join us. I assumed that most would have tuned out this discussion.

In order to adequately address your question, we’ll have to introduce another physics term: Work is what you get when a power source (e.g. muscles) operates over a period of time.

Power * Time = Work

In terms of what this means in terms of velocity of the clubhead, you can use this formula:

Work = Kinetic energy (KE) = 1/2mv*v (1/2 mass times velocity squared)

So let's say that the 200 yds swing had a clubhead speed of 100 mph (not true but bear with me - just keeping it simple) and the 300yd drive had a clubhead speed of 150 mph.

This means that the differential in work as expressed as a % increase to go from 200 yds to 300 yds is:

(150*150 - 100*100)/(100*100) = 1.25 or as I said above 125%.

Stated in another way - and ignoring the units and absolute values - the 300yd swing requires 2.25 times the power source. This is actually at a minimum as there is a second factor here - namely that the more muscles you recruit (thereby increasing your rotor motor horsepower), the sooner the swing is over. Therefore you need even more muscle to do sufficient work in the shortened timeframe.

Re: the very low % ascribed to body power in studies you mentioned. Please provide references if you could. One needs to scrutinize these carefully as often they make statements like" well the hips can only more 2 mph" and do not understand anything about angular motion. Jorgenson in "The Physics of Golf" determines that only the legs contain enough muscle mass to power the golf swing.

Golfie

GMcG,
doesn't the above calculation make the assumption that all the difference in KE from 100 to 150 mph is transferred to the ball?...i don't think a 150 mph impact speed clubhead slows to 100 mph during impact...anyway, as i've said before i think it is the equation F=ma that answers the distance question and not velocity but acceleration at impact that makes the most difference (assuming equal clubs and equally good ball contact) and that is why slow easy swings with late release and therefore high late acceleration can hit the ball as far or farther than some really hard swings.

-hcw