## Wednesday, March 6, 2013

### Charged pendulum

From brilliant.org: Two point charges, each of charge q and mass m, are hung from 1 m long cords and constrained to move in the xy-plane. The charge and mass are chosen such that the when the charges are in their equilibrium position the angle $/theta$ the cords make with the vertical is 0.1 radians. The masses are placed in their equilibrium positions and then each is pulled out by some small angle 0.01 radians and released. What is the period of the resulting oscillation in seconds?