Two identical pith balls are charged by rubbing against each other. They are suspended from a horizontal rod through two strings of length 20 cm each, the separation between the suspension points being 5 cm. in equilibrium, the separation between the balls in 3 cm. Find the mass of each ball and the tension in the strings. the charge on each ball gas a magnitude `2.0 xx 10^(-8) C.`

Explanation

`Tcostheta =mg…….(i) `
` Tsintheta =F…….(ii) `
` sintheta =(1)/20 `
` costheta=sqrt(1-(1/20)^2) `
` from equation (i) and (ii), `
` tantheta=F/(mg) `
` :. m=F/g tantheta `
` or m=(9xx10^9xx(2xx10^-8)^2)/(9xx10^-4xx.98xxtantheta)`
` =8.2g `
` T=F/sintheta `
` =(9xx10^9xx(2xx10^-8)^2)/(9xx10^-4xx1/20) `
` T=8.2xx10^2N`.