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# what is limiting frictional force? Watch

1. thanks
2. (Original post by hibaj)
thanks
Frictional force is a force that resists movement between two objects. If friction is limiting, it is providing the maximum possible force it can.

To physically demonstrate this, place your hand on a surface (e.g. a desk) and very lightly try and push your hand along it. You should feel a very small force (Friction) pushing back. This force is not limiting because you are not pushing hard enough. If you push your hand harder, so it moves, then you should feel a bigger frictional force pushing your hand back - and because your hand is moving, this frictional force is limiting (it is the greatest it can be for that movement).

(Note that the point at which your hand begins to move marks the point at which friction is limiting).
3. The value of frictional force depends on the applied force to the object. The object "does not want to move" so when you put an applied force, an equal magnitude of frictional force counteracts that (kind of like reaction force). Although, there is a limit to how high the frictional force can be. The maximum value it can have is called the limiting frictional force, which is equals to the constant of proportionality times the normal load. When the applied force has the value which is greater than that, the frictional force does not increase and stays at the value of limiting frictional force. One force is greater than the other, hence the equilibrium is broken and the object moves.

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Updated: May 16, 2013
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