Interlude A: Static Friction Force

What does Static Friction Force depend on?

The types of surfaces in contact.

What does Static Friction Force not depend on?

Surface area and speed

What force is greater than kinetic friction for the same pair of contact surfaces?

Maximum static friction

When there is no other horizontal force, the static friction force is?

Zero

Newtons 1st law requires that no static fiction force act on the block

If a small horizontal force is applied, such that the block does not move, what is the static friction?

It balances the force

Fs-Fp

If the horizontal force is increased such that the block is on the verve of moving, what is the static force?

The maximum static force has been reached

How is force determined by a question?

What is the behavior of the system relative to the surface

If no relative movement, how is the static friction force found?

Must be by using Newton’s first law

When do you use the maximum static friction force?

When the object is on the verge of sliding

When do you use static friction force?

When the object is not sliding

When do you use kinetic friction force?

When an object is sliding

When is the stationary particle model appropriate?

When the block is on the verge of moving but not moving yet