Question

Two identical, small balls are suspended by separate 0.25m threads that are attached to a common point on the ceiling. Each ball has a mass of 8.0 x 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 36 degrees between the threads.

A) Determine the charge on each ball

B) Determine the tension in the threads

Answers

First find the tension in the thread:
Tcos18 = mg
Now the charge
Tsin18 = kq^2/r
Find r from geometry
.25 sin18 = r/2
when I find the tension in the thread, do I plug in the mass of the ball in the equation?

Also,to find the charge, wouldn't the angle be 36 degrees so why would I use .25sin18 rather than .25sin36?

Thirdly, for the part about kq^2/r... what would be the q value and would the r value be 0.25 or would it be half of 0.25?

Please answer all my questions. I don't understand this problem!

Thank you!!!
half of 36 is 18 degrees, so u would use 18 degrees rather than 36.
CAN SOMEONE PLEASE EXPLAIN WHAT I WOULD PLUG IN FOR THE MASS (IN ORDER TO FIND THE TENSION) AND ALSO WHAT THE "Q" VALUE WOULD BE TO FIND THE CHARGE!!!
AM I SOLVING FOR THE "Q" VALUE?

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