How did you get through this algebra?
"
##\sqrt{h^2+w^2}-1##, giving a vertical force component of ##kh(1-(1+\frac{h^2}{w^2})^{-\frac 12})## per spring.
For small h this approximates a total force of magnitude ##k\frac{h^3}{w^2}##. "
Still don't see why you were writing p+d/2 / p-d/2 when it is 11/9 for 10+- 1 (where I assume 1 is d). Largest possible value would be p+d/p-d, would it not?
12b) was fine, I could do it, was not sure about the -k/m x becoming - k/m 0 or how they get the equations for the first few lines. Will look at it again.
How would I observe latex code in non-linear form when typing? i.e. \ frac a b isn't in text.