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### Like us? ## Friction Force

Friction force is usually denoted with Ff. The coefficient of friction is defined by , (pronounced mu) and is a property of the material that the object rests on. For instance, a smooth wooden coffee table would have a much lower value for than a piece of sandpaper, for example.

The formula for friction . . . → Read More: Friction Force

## Find friction force, given mass and coefficient of friction

Q: The coefficient of static friction between a book and the level surface it slides on is 0.65. If the mass of the book is 2.0 kg, what minimum initial applied force is required to slide the books across the surface?

A: State what you know.

= 0.65 m = 2.0 kg g . . . → Read More: Find friction force, given mass and coefficient of friction

## Find coefficient of friction, given force and mass

Q: An engine provides 5.0 kN of force to keep a 1600-kg vehicle moving at a uniform speed. (Air resistance is negligible.) What is the coefficient of rolling friction between the tires and the road surface?

A: First convert 5.0 kN to Newtons: F = 5.0 kN = 5000 N. (Just like 5 kg . . . → Read More: Find coefficient of friction, given force and mass