Problem 25.10: Find unknown charge on pendulum
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A charged ball with a mass of 30 grams is suspended from a string as shown. A second ball with a negative charge of 3 mC is placed on a wood table. Play the animation and move the ball on the table toward and away from the pendulum (position is given in meters and time is given in seconds). Restart.
- Find the equilibrium point of the pendulum for two different positions of the ball on the table.
- Write an expression for the change in potential energy (both gravitational and electrostatic) from one equilibrium position to the other.
- What is the charge on the pendulum? Assume that the charge on the two balls is uniformly distributed.