At a 1997 soccer match, Roberto Carlos scored a goal against the French national team that seemed physically impossible. The ball seemed to curve around the French players. Physicists couldn't explain the ball's movement:
A group of French scientists, perhaps desperate to prove that at least the laws of physics weren’t actively rooting against their national team, have been able to figure out the trajectory of the ball and, with it, an equation to describe its unusual path.
It all comes down to the fact that, when a sphere spins, its trajectory is a spiral. Usually, gravity and the relatively short distance the ball travels cover up this spiral trajectory, but Carlos was a mere 115 feet away and kicked the ball hard enough to reveal its true spiral-like path. As you can see in the diagram above, the ball would have kept spiraling if gravity (and the netting) hadn’t gotten in the way.
At the link, you can see a video of the kick.
Link | Image: New Journal of Physics
Comments (12)
You're right, thank you. I stand corrected. AND educated.
Can't deny it is extremely hard to give it that kind of spin, and that shot is noteworthy anyway, but shame on the people talking about physical impossibility or trying to explain what is already obvious. It gives science a bad name, as science doesn't cover these silly topics.
As for the final result, it was 1-1, so the Frecnh didn't loose... or flee, or go on strike...
I refuse to believe that a spherical object in motion will naturally assume a spiral path - that's nonsense.
This reminds me of the silly things people were saying about Baseball's curve ball 150 years ago. Most first year physics texts have a detailed explanation.
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@Jim M, pool and related games do use the same general principle, but the cause is friction against the table, not against air. Your example is not wrong, but it's counter-intuitive.
As for the final result, it was 1-1, so the Frecnh didn't loose... or flee, or go on strike...
Can't deny it is extremely hard to give it that kind of spin, and that shot is noteworthy anyway, but shame on the people talking about physical impossibility or trying to explain what is already obvious. It gives science a bad name, as science doesn't cover these silly topics.
You're right, thank you. I stand corrected. AND educated.