# Coriolis forces, rotating coordinate systems

1. Nov 6, 2006

### bcoats

I know that some people worship Symon's Mechanics 3rd Ed., but I find this book incredibly confusing...especially chapter 7, dealing with rotating coordinate systems. I follow the math, and perhaps the logic, but I can't even find a way to start the homework problems. The guy doesn't give any examples, and how the hell is one supposed to learn how to solve a problem when provided with nothing but dense proofs using strange notation?

For example, problem 7.7 tells us that a body is dropped from height h above the earth. We are to calculate the coriolis force as a function of time, given that it has a negligible effect on the motion, and using the velocity of a freely falling body with acceleration Ge. Neglect air resistance, assume h is small so that Ge can be taken as constant. Then, calculate the net displacement ofthe point of impact due to the coriolis force calculated previously.

OK , so Symon proves that Ge(r)=g(r)-w x (w x r). (The w represents omega, the Ge represents vector g subscript e.) I guess the coriolis force is the -2mw x d*r/dt term. How are we supposed to solve this. Are we just supposed to KNOW what w is? Nowhere in this chapter is w given for earth. I would think that maybe it would be (2pi/24hrs)*theta^ (if theta^=theta hat=unit vector in theta direction). Unfortunately, like Symon my professor rarely works examples either. I have no clue how to go about solving this or most other problems in the book. I there a web site out there that, say, gives clear, step-by-step examples for solving these type of problems? Or does anyone write a "companion book" to be read side-by-side with Symon's that actually works examples for problems like his?

Why the heck did I major in Physics???
Ben

2. Nov 6, 2006

### quasar987

The only person I ever heard mention Symon on this forum is me! But I do it for 5 I think cuz it's the only mechanics book I've read. :P

I wrote a light "summary" of the chapter on rotating coordinate systems a while back that at least answers your uncertainty regarding that the coriolis force is. Here's the thread.