Question

Two identical small insulating balls are suspended by separate 0.26-m threads that are attached to a common point on the ceiling. Each ball has a mass of 7.75 10^-4 kg. Initially the balls are uncharged and hang straight down. They are then given identical positive charges and, as a result, spread apart with an angle of 35° between the threads. (a) Determine the charge on each ball. (answer in C)

Answer 1

charge on each ball is 8.07 *10{-8} C

Step-by-step explanation:

given data:

L = 0.26 m

m = 7.75 *10^-4 Kg

`\theta = (35)/(2) degree = 17.5 degree`

let charge on each ball is q

let tension in the string is T

so force will be

T\times cos(17.5) = mg

`T* sin(17.5) =(kq^2)/((2Lsin(17.5))^2)`

`T * cos(17.5 degree) = 7.75 *10^(-4)* 9.8` ----(1)

`T* sin(17.5 degree) = (9 *10^9 * (q)^2)/((2 * 0.26 sin(17.5 degree))^2)` ---(2)

solving 1 and 2 for Tension T and charge q we get

T = 0.00796 N

`q = 8.07 *10^(-8) C`

charge on each ball is 8.07 *10{-8} C