We have now been introduced to Newton’s three laws, and to the three special forces Weight, the Normal Force, and the Tension Force.  This lecture will introduce us to the final two special forces: Friction and the Spring Force.  We will then work examples putting together everything that we’ve had so far with forces. 

When working through this material, it is important to keep in mind that we are basically doing the same thing over and over again:  We draw a simple picture of the set-up, we draw a Free-Body Diagram of the object(s) of interest, define the symbols being used in the problem, and then use the FBD to help us write down Newton’s 2nd law in component form.  (We do this for each FBD if there are multiple objects being considered.)  This leaves us with a set of simultaneous equations to solve for the desired unknowns, which is just a bunch of algebra. If nothing else, these problems will exercise your algebra skills!  (I know — just what you wanted...!)