Question

Can someone help me with this problem please from general physics 2.

The figure shows two tiny 5.0-g spheres suspended from very light 1.0-m-long thread; The spheres repel each other after each one is given the same positive charge and hang at rest when b = 4.1 degree. What is the charge on each sphere? (k= 1/4 pi epsilon 0 = 9.0 times 10^9 N middot m^2/C^2)

Answer 1

Option (B) 89nC is the correct answer.

Explanation:

Here, resolving the force component, you will get -

mg sin theta = Eq cos theta

=> q = mgtan theta/E

Now, from the expression, E = [1/(4*pi*epcilon)]q/r^2 and putting the values -

We gert, E = 39505 N/C

Therefore, q = (5x10^-3x9.81xtan4.1) / 39505 = 89x10^-9 C = 89 nC