posted by Ann on .
Two identical balls each have a charge of -7.5x10^-6C. The balls hang from identical strings that are 8‹ from the vertical because of the repulsive force between the charged balls. The balls are separated by a distance of 10cm. What is the tension in one of the strings? What is the mass of one of the balls?
I drew a free body diagram for the right ball. I think it should have Ft going to the Northwest, Fg to the southeast and a Fe to the east. Where do I go from here to get tension and mass?
Hmmm. Find the angle. I cant decipher your problem, but use the distances you cited to do that.
Then, use the forces: tanTheta= electrical force/gravity force.
You can from that calculate mg.
/ | | \
o | | o
o=ball, /=string, |=vertical
8‹between / and |
10cm between the balls