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How far will a person slide if they are sliding at 3m/s and the coefficient of friction between the floor and their feet is 0.5
Sorry, Halls, that's wrong. The mass cancels.Originally posted by HallsofIvy
There's not enough information. You would have to know the person's weight (or mass) to calculate the actual friction force (friction coefficient times weight). That would determine the distance.
Originally posted by HallsofIvy
There's not enough information. You would have to know the person's weight (or mass) to calculate the actual friction force (friction coefficient times weight). That would determine the distance.
Originally posted by Doc Al
Not wrong, just a little wasted effort. Looking at your own equations, you can see that the mass cancels (as chroot pointed out) so it really is extraneous information.
Resist the temptation to start plugging in numbers prematurely. Figure things out symbolically as much as you can, then plug in the numbers.
mass cancels out with mass. it's a mathematical "trick".Originally posted by marshall4
What does the mass cancel out with?
With itself, of course! (D'oh!)Originally posted by marshall4
What does the mass cancel out with?
Tires are quite special, because the deform, heat up, and become greasy as they are used. That does not mean that the area is important in determining friction -- in general, it is not.Originally posted by toa
The answers posted seem to be in nice accordance with the physics I was taught in high school. However, in practice they fail dismally, unless one at least brings the area of contact between the two surfaces into the equation. There is a reason formula one cars have tyres as wide as a barn door, and that the trimming of cars usually involves changing to wider tyres. I think there is some relationship which dictates that the greater the area, the greater the friction becomes. Does anyone know anything about this?