So my one class is using the book Nonlinear Dynamics and Chaos by Steven H. Strogatz, and I've been struggling a lot to keep up, does anyone here have some experience with that book or the material in it?

For example one of our problems:

Nonlinear Dynamics and Chaos-problem.png

I've been having the most trouble with Chapter 6 - the Phase Plane of 2 dimensional nonlinear systems starting with conservative systems and quantities.. part of the problem might be I haven't taken a physics course since high school and I haven't worked much with matrices in 2 years...

A. a) Write the rigid body equations in terms of the angular momenta and

show they evolve on the momentum sphere.

b) Show that while the energy is conserved it is not a Lyapunov function

for the possibly stable equilibria.

If someone could just take the time to walk me through these problems and explain the terminology and where these variables are coming from that would be great. I wish I could be more specific about these problems but at this point I'm just so lost I don't know where to even start.