Question

Two small identical balls of mass 0.04 kg are suspended from a fixed point on a rigid surface with the help of 2 threads of 1m length. Both the balls are given equal and similar charges so that they repel each other till the angle between them is 60 degree. Find the value of charge given to each ball

Answer 1

Answer:

Given that two pith balls of same weight are suspended from same point by means of silk threads of equal length. On charging the pith balls equally, they repel each other. We have to find forces responsible to remain under equilibrium.

According to the figure,

At equilibrium, force of repulsion is balanced by the sin component of tension in the string i.e, F=Tsinθ ...(i)

Weight is balanced by the cos component of the tension mg=Tcosθ ...(ii)

where m= mass of each pith ball

T= tension in the string

F= force of repulsion

g= acceleration due to gravity

Dividing (i) and (ii), tanθ=

mg

F

⇒F=mgtanθ

This is the force under equilibrium.