# Coefficient of Sliding Friction

1. Mar 23, 2005

### vitaly

Does anybody know a website that gives sliding friction (blocks on planes, etc.) example problems? I am trying to figure out how to calculate the coefficient of sliding friction, but I'm having problems doing so.

I know the general equation is:
coefficient of sliding friction = friction force of motion / normal force.

My questions are:
1) Is the normal force just the mass of the object that is sliding?
2) What exactly is the "friction force of motion"?
3) Can anybody include an example problem to find the coefficient of sliding friction?

Thanks for all the help.

2. Mar 23, 2005

### JFo

1) The normal force comes about when two surfaces are in contact with each other, the normal force is always perpendicular to the surface. (The friction can be thought of as the component of force from contact that is parallel to the surface.)

2) The frictional force of motion is actually very hard to define. It occurs due to the interactions between the molecules of the two surfaces in contact. It always acts to oppose the direction of motion on an object.

3) Do a search on this forum for friction, and I'm sure you'll find a ton of examples.