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February 26, 2008
Drag Effect on Curling Rocks
I had been hearing about the "drag effect" or "drag theory" of curling rocks on television for a few years, but up until last week I had never truly seen a clear example of it. Now I have, and here's the video and an explanation of what's going on.
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First, watch the video a few times so that you see the setup of the rocks in the house, and also the shot that Jennifer Jones plays:
I've enlarged one frame of video to show the setup and alignment of the rocks in the house. I've also drawn blue arrows, showing the path that the yellow rock should have normally taken if it wasn't frozen with the struck rock:
The green arrows show the path that the struck red rock will take. Since these two rocks are indeed frozen, as the red rock starts to move down this path the striking band of the red rock "grabs" the striking band of the yellow rock through friction and applies a force on the yellow rock in the direction of the green arrow.
To figure out why the rock ends up going a completely different direction than either the green or blue arrows indicate, all we need is some high school physics: the addition of vectors.
A vector represents both the magnitude and direction of force. I have attempted to draw the green and blue vectors to scale. Moving the green vector so that it is head-to-tail with the blue vector, the result is the yellow vector. Of course this is all manufactured by me to work out correctly, but you get the idea.
Curling rock drag effect is something that they talk about on television far more often than I've actually ever seen it (I suppose it's something else for the commentators to mention). Or perhaps the drag effects just weren't as obvious and pronounced as in the video clip above.
Next week I'm going to set up a few practice situations and try to simulate the drag effect by myself. I'm not sure that I'll ever see this effect myself in a real game, but at least now I'm convinced that it's physically possible!
Posted by Hammer at 12:02 PM | Comments (12)