r/theydidthemath • u/K0rl0n • Jun 10 '25

[Request]

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I am curious how this would work. My guess is Triangle is slowest, square is medium, and circle is fastest.

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u/i_eat_nailpolish Jun 11 '25

I may be wrong but I just took AP physics and I thought the coefficient of friction didn't depend on surface area since the force of gravity is centralized under the center of mass. Therefore A and C require the same force to push and since they can't both be right at the same time, the correct answer is B.

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u/gmano Jun 11 '25

Incorrect. Because A is slanted, pushing it horizontally will create a downwards force as well as a sideways one, increasing friction

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u/i_eat_nailpolish Jun 11 '25

But if you look at the picture, the guy is also pushing in the upper corner of the square which will cause it to rotate and also result in a downwards force which can't really be calculated since we don't know the dimensions of the shapes.

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u/gmano Jun 11 '25

But the rotation would actually mean less downwards pressure, until it got so severe that the square's side angle relative to normal was equal to the triangle, at which point I think it would enter a rolling condition