Thanks,
@wrobel, for posting these problem sets.
How do these problems compare to Goldstein, Marion, or Taylor's books?
Are they undergraduate or graduate level?
This could help other posters decide whether to attempt them.
Is there one problem that really stands out?
When I was an undergrad in the 1970s, we used Marion (I never knew why we didn't use Goldstein) in undergrad Classical Mechanics.
For me, the one problem that stands out is the time it takes an object under Earth's gravitational pull from deep space to fall to Earth.
I think it took 9/11 of its time to fall halfway.
My fellow students and I struggled over that problem for a week. While in the Physics Dept breakroom, one prof comes in and asks, "What's going on?"
We told him about the problem of relating the time of fall to varying gravitational acceleration. We just couldn't find a scheme that didn't blow up in our faces.
His response was look at Kepler's law of equal areas in equal time and imagine the falling object is in a highly elliptical orbit. We were dumbfounded that the answer became so obvious.
As students, we never considered thinking outside the box, limiting ourselves to what the question gave us and what was in the chapter.
I think they need a course on that alone, where a student's first homework is to sit inside a box and ponder some question.