The Force of Friction Friction is a force that is created whenever two surfaces move or try to move across each other. Friction always opposes the motion or attempted motion of one surface across another surface.
Friction is dependant on the texture of both surfaces.
In this simulation you see a block sitting on a level table. Each time you press the button the applied force will increase. As you use this simulation there are several things you should notice. The force of friction depends upon both surfaces in contact and the normal force . A mathematical relationship can be created that relates the force of friction for any two surfaces to the normal force.