Acceleration of golf club hitting a ball

[Jgolf]

The great Ben Hogan said he learned from a physics book when he was on the PGA Tour that if the golf club head is still accelerating AFTER it has struck the golf ball, the result is a straighter shot on line to the target. I can't find any examples of what he is talking about in the physics books I've looked at...any help is appreciated...I'm not a physics major. Thank you, John

 

[russ_watters]

Welcome to PF!

It is tough to know exactly what he is referring to, but there are a couple of possibilities:
1. The way we coordinate our movements affects the timing and alignment of the impact (duh, but I'll explain...). A smooth, continuous motion is simpler to achieve than one that changes over time. As a result, smooth, continuous acceleration that you stop only after you've made contact produces the best results. To be clear, though, the acceleration of the club-head isn't exactly constant, it is the various rotations (hips, shoulders, wrists) that should each be smooth - but they combine to produce a more complicated pattern of motion.

2. The shaft of the club is elastic. As you swing, it stores and releases elastic energy, which also accelerates the club. However, it was my understanding that you want the club back at straight (moving through straight) when you make contact, and as it passes straight, the additional force from the elasticity drops to zero. So I'm not certain how that could relate.

 

[Jgolf]

Russ, many thanks, a Golf pro who played on the LPGA Tour that Hogan mentored said he passed it along to her and also in one of his golf books he stated that maximum club head speed occurs right after impact, not during impact...I know that when the club head hits the ball there is, I think, some slowing down of the acceleration, or at least that's what I recall reading somewhere...that's why I'm trying to get some scientific clarification, etc...again, Thanks, John

 

[A.T.]

maximum club head speed occurs right after impact, not during impact

There is lots of slow motion footage of the impact on the net, that could be used to check this. But it's usually under lab conditions, so it might not be executed as suggested by Hogan.

From physics standpoint: If the head doesn't slow down at impact, the contact time is longer so more momentum is transferred to the ball.

 

[Jgolf]

A.T. Thanks for the suggestion, I'll check it out...John