Problem with a physical equation When I solved a physics problem, I found a little problem of math calculation at :
$$E=E_{c}+E_{p}= \frac{ms'^2}{2}+ \frac{mgs^2}{8R} ~~~~\text{(1)}$$
(this is the equation where I met the problem for solving it). The problem said that are no neconservative force, so our $E$ will be zero. 
I derivate the equation $\text{(1)}$ and I obtained:
$$s''+ \frac{gs}{4R} =0 ~~~~\text{(2)} $$ 
Now, the problem asks for pulsation. I don't know how to find angular-frequency [rad/s] beginning from the equation $\text{(2)}$. Any help or hint will be receive very well !!

Just from glancing at your problem, it looks like the differential equation will have periodic solutions of the form 
$$
s (t) = A \sin \sqrt{ \frac{g}{4R} } t + B \cos \sqrt{ \frac{g}{4R} } t .
$$
In which case, the frequency of oscillation is given by the quantity $\sqrt{ \frac{g}{4R} }$. I don't know if that answers your question.
