# Frictional force depends on roughness of surface

Q.  Frictional force depends on ________
- Published on 18 Sep 15

a. surface area in contact
b. roughness of surface
c. both a. and b.
d. none of the above

#### Discussion

• Sravanthi   -Posted on 16 Dec 15
According to Coulomb's law,

- Frictional force depends on roughness of surface and is independent of the surface area in contact. It also depends upon magnitude of forces which hold the bodies together.

- If the surfaces are smooth then force required to move them is less and if they are rough greater amount of force is required.

- Friction between smooth surfaces is more due to attractive electrostatic forces between the atoms.

When an object moves on another surface, it is pressed against the surface due to gravity pull acting upon it. This force is equal to the weight of the object. As weight of body increases, resistance also increases between the moving surfaces in contact.

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