Head weight versus distance

When I recently took up golf again following a lengthly hiatus, I was generously given a couple of slightly used Burner drivers. The thing I noticed most of all was how light the heads were. I had trouble adjusting to the feel of these clubs.

It was explained to me that the manufacturers design drivers primarily for distance, which means head speed. I assume the thinking is that the average golfer can increase the head speed of his driver if there is less mass to accelerate.

I can't argue with the marketing, but for me it didn't work. The obvious fix was to add a little weight to the head, which I did.

I took both drivers out to the range yesterday to see which one hit longer. I was curious to see how the added weight effected my distance. It was close, but the added weight increased my distance by about 10-20 yards.

This got me thinking about the physics involved. A heavier mass traveling at the same speed is going to impart more energy to the ball than a lighter mass. My swing speed is primarily governed by my ability to rotate my body and generate torque. A few extra grams on the end of the shaft isn't going to slow things down much, but it will impart more energy..

Therefore, it only makes sense to use the heaviest head I can swing comfortably. I just wonder how it effects the dynamics of the shaft.

That may be so. The swing is all about timing, so maybe that's part of it too.

Kinetic energy is calculated using the formula: KE = 1/2 mass x velocity squared. Momentum (P) is calculated with P = Mass x Velocity.

A small change in velocity creates a large increase in Kinetic energy. A small increase in mass has little effect with respect to KE.

However, a small change in mass has much more effect with regards to momentum.

The question is: which has more effect imparting energy to the ball, kinetic energy or momentum?

My guess, from a purely physics perspective, would be KE. A higher club head speed would impart far more energy to the ball. Nevertheless, we have to think about what is happening to the ball at the point of impact. It's getting squished and accelerated.

At the point of contact, a lighter head will decelerate at a faster rate than a heavier head. The heavier head maintains greater velocity until the ball leaves the face. This means the ball probably spends a little more time on the face of the heavier club, where it develops a greater amount of deformity and has more time to gain energy and accelerate.

Then again, the amount of increased KE from the lighter head may do the same thing.

Interesting to think about anyway.