The electrostatic pendulum

We will try to measure electric force with the help of an instrument which is easy to understand: the electrostatic pendulum. We shall see how this instrument lets us measure the force acting on a body. You can graduate the magnitude of the force acting on the pendulum on the right.

 

 













When you click on next you will see how to use this pendulum to measure the force between two charged bodies.


Whether you modify the mass (and thus the weight) or you modify the horizontal force, the angle varies and equilibrium is reached among the three forces acting on the bob of the pendulum:

 

 

The force applied F, the tension of the string T, and the weight of the body P.