Question

Two Styrofoam balls with the same mass m = 9.00 × 10−8 kg and the same positive charge Q are suspended from the same point by insulating threads of length L = 0.705 m. The separation of the balls is d = 0.0221 m. What is the charge Q?

Answer 1

`q = 3.87 * 10^(-11) C`

Step-by-step explanation:

As we know that the two styrofoam balls are suspended in equilibrium

so we will have

`Tcos\theta = mg`

`Tsin\theta = (kqq)/(d^2)`

also we know that

`sin\theta = (d)/(2L)`

`sin\theta = (0.0221)/(2(0.705))`

`\theta = sin^(-1)(0.0313) = 1.79 degree`

so we will have

now from above two equations we have

`tan\theta = (kq^2)/(mgd^2)`

`tan(1.79) = ((9* 10^9)q^2)/((9* 10^(-8))(9.81)(0.0221)^2)`

`q = 3.87 * 10^(-11) C`