# Parallelogram with springs [closed]

The situation is represented on the picture. For the first question , I tried to do it with the conservation of mechanical energy. So I have the following $$E = E_{cin} + E_{pot},mg + E_{pot}$$,spring . But then I have a hard time expressing these. In order to find the maximal speed of P, I have to consider the case were potential energy is minimal, but writing the expression depending on $$\phi$$ is confusing. The second picture is what I managed to do until now.

b) Find the differential equation for $$\phi(t)$$ from a first integral of the movement.What is the pulsation of the small oscillations around the stable equilibrium position?