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#1 2007-10-24 02:53:17

Daniel123
Member
Registered: 2007-05-23
Posts: 663

Friction

Does anyone mind explaining to me why F_max = μR?

What does R have to do with it?

Thanks.

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#2 2007-10-24 02:58:09

Daniel123
Member
Registered: 2007-05-23
Posts: 663

Re: Friction

Actually, I get it.

But why say R, and not W? They're the same, aren't they? And it is the weight that causes the reaction.

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#3 2007-10-24 17:35:03

landof+
Member
Registered: 2007-03-24
Posts: 131

Re: Friction

Excuse me, I don't want to sound rude but is R a variable to the equation? Independent? Dependent?

I shall be on leave until I say so...

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#4 2007-10-24 23:50:03

mathsyperson
Moderator
Registered: 2005-06-22
Posts: 4,900

Re: Friction

R is the reaction force. If you're standing on the ground, then your weight is pushing on the ground and so the ground exerts a reaction force which stops you falling through it.

R isn't always the same as W, that's only true when the ground is flat. Also, there could be situations where W isn't the only force in play (for example, steel block being pulled to the floor by a magnet). Then R would be the reaction against both the weight and the magnetic attraction.

Why did the vector cross the road?
It wanted to be normal.

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