# Applying different surfaces to balls

I get confused thinking about the physics of what golfers call a “bladed” shot, and I want you to too. In a classic bladed shot the leading (bottom) EDGE of the iron, usually a more lofted one, strikes the horizontal equator of the ball, which is way too high. In a normal shot the center of the FACE of the club strikes the ball.

Just before the ball is struck it is spherical, of course, and shortly after it is struck it loses contact with the club and decompresses, i.e., it returns to being spherical. But in between, for those few milliseconds, I’m quite sure the ball is deformed by the surface hitting it.

If I may idealize here, imagine a golf ball being struck, at a controlled speed and at and continuously parallel to its horizontal equator, by either a flat surface or a short rectangle. Assume the width and height of the flat striker are significantly larger than the ball’s. And assume that the width of the rectangular striker is significantly larger than the ball’s diameter but that the height is, let’s say, 10% of the height of the ball.

Assume that the strikers are of equal mass. And assume the strikers are incompressible but that the ball is not.

When I think about the physics during the moments of impact it seems to me that in the case of the planar striker the total force is spread out over a certain circular area at a certain number of pounds per square inch, whereas in the case of the more nearly linear striker that same force is spread out over a smaller, rectangular area but at a higher psi, with the result being the same total impelling power (area times psi) being applied with either shot. Experience, however, tells me the bladed shot goes farther.

Also, could it be that that the planar striker is in contact with the ball for a longer or shorter period than the rectangular one, in which case maybe you’d multiply area by psi by time?

I myself have never bladed a golf shot (and I’ve never told a lie), but I’ve seen it done many times by the guys I play with.

Under idealized circumstances, which striking surface will propel the ball farther, a 100% endless plane or a 10% edge?

Is this similar to whether you can kick a soccer ball farher with the toe of your foot or the top of it? If so, what’s the answer to that?

Thanks.

–JohnEGee, guest

I’m neither a physicist nor a golfer, so be warned that this answer may be bad science.

Picturing this problem in my head, though, it seems that the blade shot, if perfectly applied, would impart nearly all of its force to the ball. The shot on the face of the club, though, imparts some of its force to spinning the ball. The club might even go past the ball, cutting under it. Using an iron is supposed to give you spin and rise, not distance, right.

If you want distance, why use a high-numbered iron anyway? I don’t know a lot about golf, but I’ve heard you get into theologic issues when discussing The One Iron. From your description, a blade shot means hitting a ball dead center with a part of the club an eighth of an inch thick. Isn’t the game frustrating enough for you without trying for a near-impossible feat like that?

One factor you’re possibly overlooking in your simplified model is that when you hit a normal golf shot with a lofty club, the ball doesn’t take all the forward force of the club, but lifts up as the club travels underneath it. This results in some forward force getting translated into upward force. When you hit a bladed shot, this doesn’t happen, so all the force is applied towards moving the ball forward.

Imagine you’re hitting with a hypothetical 17-iron with a 75 degree club face angle. A perfect swing will result in the ball getting a massive amount of backspin and an really steep trajectory, but without much forward motion. But if you hit a bladed shot with the same club, the ball will go straight forward.

The golf ball isn’t on some kind of conveyor belt, is it?

Do you mean as in, “Can a golf ball on a treadmill reach the green in two?”

What do you mean “reach the green in two?” There is not such thing possible. When you see guys doing it on TV it’s nothing but computer animation. They can’t fool me because I have experience on my side.

PS Whenever I blade an approach I repeat to myself over and over, “Hit down on the ball, dummy, and that won’t happen.” And it works too, until the next time.

[/quote]
What do you mean “reach the green in two?” There is not such thing possible. When you see guys doing it on TV it’s nothing but computer animation. They can’t fool me because I have experience on my side.
[/quote]

I just now read the above, and it’s hilarious.