1. Miscellaneous Forces

2. Weight
Weight is the force of gravity upon an object. This force is represented by the symbol Fg (units of Newtons)
Acceleration of gravity on the earth is always m/s/s, so weight can be calculated by multiplying the mass and m/s/s

3. Normal Force
Normal Force is the force of a surface on an object, and acts against the force of gravity (weight). It is always perpendicular to the contact surface. It is represented by Fn

4. Force of Friction Friction is a force that opposes applied force
Static friction is the force that is exerted on a motionless object, and is always equal but opposite to an applied force. It is represented by Fs.
There is a limit where the static friction can no longer keep the object motionless. This limit is called the Fs,max

5. Force of Friction
Kinetic friction is the force that opposes motion of a moving object. It is a fixed amount that depends on the surfaces involved. It is represented by the symbol Fk

6. Force of Friction
The coefficient of friction describes the relative amount of friction between two surfaces. It is represented by μs or μk
It can be calculated by:
μs= Fs,max / Fn
μk = Fk / Fn
See page 102 for a table of values