Saturday, January 16, 2010
Irodov Problem 3.3
At any given time there are three forces acting on the spheres, i) the tension in the string T, ii) the force of gravity mg acting downwards and iii) the electrostatic repulsive force between the sphere given by . The forces responsible for the motion of the pendulum are along the tangential direction perpendicular to the string. Along this direction there are two forces acting on the sphere, i) the component of the force of gravity and ii) the component of the electrostatic force .
In order for the sphere to be in equilibrium we have,
For , we have
From (1),(2a) and (2b) we have,
As the charge slowly leaks from the spheres the electrostatic force between the spheres decreases and the equilibrium distance between the spheres decreases. Hence, we have,
Posted by Krishna Kant Chintalapudi at 7:16 PM