JacksonStone wrote:
sharkman wrote:
An average golfer's swing is about 85mph which is 125 ft/sec. So the starting velocity is TWENTYONE times greater than a watch hitting a wall at walking speed(4mph)....There are other factors such as the amount of force absorbed by the club head and shaft, collapse of the wrists, etc...that would decrease the forces on the watch in the golf swing scenario.
I'm no physicist, nor a golfer for that matter, but it seems to me that the Gs at the point of impact - where the club head meets the ball - would be the greatest, and would lessen the closer one gets to the pivot point of the swing. Assuming the pivot point in a golf swing is somewhere between the shoulders and the elbows, it seems the wrists are closer to the pivot point than the point of impact. At any rate, to bear the full brunt of force in a golf club swing, wouldn't the watch would need to be mounted on the head of the club, rather than on your wrist? Conversely, when you bang a watch into a wall at walking speed, the watch is inherently at the point of impact.
I know a couple biomechanical engineers who would be happy to figure this out. They charge a lot though. But yes, presumably the average golfer gets to 86mph -125ft/sec at the moment of impact - either with the ball or the ground. Your arms, wrists, and hands are moving at 125ft/sec as well. IF you bury the club and otherwise keep your footing, everything stops and the delta V occurs in maybe 50 milliseconds. Bam! As I said before, some of the energy will dissipate in deformation of the club shaft and induced movement to the wrists, but it is still going to be many times the gs of a wall strike. A nice perfect swing without a hitch will produce 150g. That isn't produced by the impact with the ball - the ball impact is negligible due to, among other things, the club face and ball having HUGE coefficients of restitution. Rather, it's simply the process of the swing going to Zero ft/sec at the end of the swing. Your Delta V on an average swing is 125 ft/sec, but it occurs over nearly a full second, not milliseconds. The time factor greatly impacts the amount of gs.
Look at it this way - if I'm sitting in the driver's seat of a car and get from behind by a target vehicle, my vehicle accelerates from zero to some velocity (Delta V). So do I. Once you know the Delta V and impulse, you can calculate g (we've all been using G, but that is the vertical force of gravity - g is the horizontal application in equivalent measurements). If I am strapped the the rear bumper, the g (acceleration I experience is no different than if strapped to the front bumper. It's effectively the acceleration of the car for both guys, even though the guy in front is farther from the impact point. I'm just along for the ride. Granted, perhaps the poor dude on the back bumper has broken bones from blunt force trauma. But the effect of horizontal gs on him is no different than the guy in the front.
And the golfer, a good golfer, who golfs once a week and spends a bit of time on the range before the round swings about 200 times per week. How many times do any of us bang our watches full force and straight on into a wall?