As a captain of the curling team, I am always looking
for ways to improve our game; thankfully, I think what we’ve learned in Physics
111 this year will help us defend our national ranking.
The other think to consider is when we’re trying to throw take out
shots. Below is a video of some really impressive take out shots:
In my opinion, the take out shots are the most fun to
throw, but getting enough velocity on the stone can be difficult. In relating initial and final velocities of
each stone, we can assume that the stones experience a perfectly elastic head-on collision (they make a noise when they collide, so energy is not technically conserved),
ignoring the static friction between the stone and the ice.
When curling, the stone that is hit (1) has an initial velocity of 0
m/s, and the stone doing the hitting (2) has a final velocity of 0 m/s. With
this, we can see:
which means that the stone that is hit leaves the collision with the
same velocity as it was hit with (in reality, slightly less) in the same
direction of motion as the hitting stone. Because the stones are moving around
2 m/s at this point, the house (scoring region on the ice) has 3.5m radius, and
velocity is proportional to distance traveled, this time not ignoring
friction, a change in 1 m/s in either direction can mean the difference between
hitting the stone out of the house, or having it stick around. This difference
in distance traveled can mean the difference between scoring in the end, or
losing the end, which will have major ramifications in point totals for the
game, and throwing order for the following end.
Another aspect of
curling that physics can explain is the importance of sweeping stones. When a
stone is thrown, if it does not have the correct initial velocity for the type
of shot you are trying to make, sweeping the stone can make the stone travel
farther. How can this be so? Conservation of energy:
If we are trying to see what makes the stone go further without having
changed the initial velocity, then the only variable that can logically be
changing is μ. Sweeping
melts the pebbles on the ice, thus lowering the coefficient of friction, which
is what makes the stone go farther when it is swept. Another interesting and
less understood part of sweeping, is that it makes the stone curl less; this
might be better understood if we look at why a stone curls at all.
Although there is a lot of curling that Physics 111
can explain to us, there is one thing that is still not understood about
curling: why it is that the stone curls in the direction of motion? If you were
to push a spinning cup on a flat table, the cup would ultimately curl in the
opposite direction of the cup’s spin. So why doesn’t the curling stone do the same
thing? The answer is in the pebbling of the ice. This video does a good job of
exploring why it might be so:
The short answer: we don’t really know why it is, but hopefully, as we
move into rotational motion, we’ll be able to understand better the physics of
curling.
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