cross-posted from: https://hexbear.net/post/7671573
Sweden knew Canada’s Marc Kennedy was a notorious cheater.
So they set up a camera at the ‘hog line’ to record it.
And caught him doing it at the Olympics.
cross-posted from: https://hexbear.net/post/7671573
Sweden knew Canada’s Marc Kennedy was a notorious cheater.
So they set up a camera at the ‘hog line’ to record it.
And caught him doing it at the Olympics.
This is a fun little physics problem.
The CoF of a curling stone on ice appears to be between .006 and .016 depending on fast its sliding.
So with a CoF of .006 that 40lb chunk of granite has an effective weight of just four ounces relative to that same chunk of granite at a CoF of 1. With a CoF of .016 it’s relative weight is 9 ounces.
So if the finger brush is in either the X or Y axis then basically anything more than what it takes to press a key on your keyboard will have an effect.
Trying to stop the stone from rotating is a whole different matter because then you’re working against it’s stored inertia and that will be much much higher. No way to calculate that though unless you know it’s rate of spin.
I appreciate you finding that article - interesting one.
I’m very much amateur curler, and can’t see how that tiny touch would impact it, but maybe it does at that level of competition.
Using a perfect shot to stop on the button with no spin, and energy= all kinetic (1/2mv2) =friction energy(F*deltaX), we get a release speed of 1.8m/s (with a .006 coefficient), and a 2.98m/s speed (with a 0.016 coefficient).
Using the same equation, I go ahead and rerun the number, but adding a distance of 0.1m, a value I used as a good approximation of a reliable accuracy of an Olympic throw, and a time of 0.2s (the approximate time I estimated based on the video), which means a deltaX2 of 0.36m, or 0.596m.
1/2mv2+fapplieddeltaX2 = ffrictiondeltaX Fapplied comes out to 0.326N to 0.526N which is a miniscule amount.
That seems to indicate that a tiny touch DOES have the potential to make a significant difference. Some sources say 0.25 to 0.5N is required for a keyboard press, so its roughly on par with that
But, how much of a difference does the sweeping make on stone speed? Its easy to say that tiny change can impact things, but how does it compare to, say, sweeping hard vs not sweeping?
This study shows a sweeping change of 45+/-8mm. Thus a change of 25% on top of that is not insignificant.
So the last question is, does it make sense for someone to train specifically by cheating this way rather than doing it right and just pushing off with a more accurate force? That’s likely going to be subjective, but seems difficult to me.
Who knows, maybe this is a crutch and it is making a difference. Sounds like they need to stop doing it any case, whether a way they’ve trained or not. Or wear a camera showing they don’t touch the rock and just hover their finger behind it.