This is a requested post. Clearly, I do requests. The idea here is that I am going to give all the details needed to determine the equation of motion (and then model it) for a basic pendulum. Warning: ...

This post has been sitting in my mind for quite some time. Really, it is about mechanics - not about pendulums. What is the goal in mechanics (classical mechanics, if you like)? Generally, it is to ...

With the polar description, we write the velocity and acceleration vectors for a point in terms of the polar unit vectors e_r and e_theta. Recall that e_r points outward from the observer O and the ...