A mass m is attached to a massless rod of length L to make a pendulum. In addition, when the rod is vertical, two relaxed springs with constants k1 and k2 are attached on either side of the mass to walls. What is the period of oscillation. I started by writing the potential energy as a function of theta, and then differentiating it twice to get the k. But I haven't had any success. The problem is kind of confusing, because it doesn't give the length of the spring. So this seems to imply the approximation that the change in length of the string is just the change in the horizontal distance of the mass, which also doesn't make sense, because this in turn implies that there is no horizontal motion and therefore the gravity has no effect. So i'm confused.