Question

The angle between two pith balls if 40 degrees. Each pith ball has a mass of 0.3kg and the length of the string is 0.3m. Find the weight, electrostatic force between them, and the charge on each ball assuming the charges are equal.

Answer 1

Draw a free body diagram, representing all the forces on each ball.
Forces on each ball :-
1) weight
2) elecrostatic force
3) tension force

Answer 2

sorry about the long wait

Answer 3

I found weight to be 1.9 N

Answer 4

but im having trouble finsing the electrostatic forces because i cannot find out what the radius is.

Answer 5

is that the diagram?

Answer 6

i think your question pertains to the equilibrium condition of the 2 masses
if it is so then vertical component of the tension cancels out the weight.
then electrostatic force = T cos 70
(if u take the line joining both of them as x axis and the perpendicular as y axis then the tension makes an angle of 70 degrees with the x axis)
the radius is 0.6 cos 70
u will have only one unknown that is q
and i already told u that Tsin 70 = mg
best of luck !