A simple pendulum is made from a L long string and a small ball, mass=m, attached to its free end. The ball is pulled to one side through a small angle and then released from rest.
a) Proof that the momentum (parallel with tangential movement), is (dp/dt)=-mgsin?=-mgsin(s/L) Theta being the angle and s=L?.
b) Write the lenght of the curve s(t) and specify the time period for small oscillations.