The Force of Friction

Friction—
• the resistive force that opposes the motion or attempted motion of an object through a fluid or past another object with which it is in contact
• always acts in a direction to oppose motion
• the resistive force that opposes the motion or attempted motion of an object through a fluid or past another object with which it is in contact
• always acts in a direction to oppose motion
• between two surfaces, the amount depends on the kinds of material and how much they are pressed together
• due to surface bumps and also to the stickiness of atoms on the surfaces of the two materials

Net Force—
• Force is simply a push or a pull
• Net Force is a combination of all forces that act on an object. It is the net force that changes an object’s states of motion.

The equilibrium rule:
The vector sum of forces acting on a non-accelerating object or system of objects equals zero.

Mathematical notation: ΣF=0.

- Jackie