Question

PHYSICS ork Chapter 16 Question 3 (of 10) value: 10.00 points 1 out of 8 attempts ASSistance Two Styrofoam balls with the same mass m 7.40x10 kg and the same positive charge 0 are suspended from the same point by insulating threads of length L -0.950 m (the figure below). The separation of the balls isd -0.0300 m. What is the charge e? Check My Work View Hint View Question Show Me Guided Solution Practice This Quest Print Question Help Report a Problem nC

Answer 1

  Let the string make an angle of theta with vertical in equilibrium.then sin theta = (0.0300/2)/0.950 = 0.0157 and

cos theta = (4/7)sqrt(3). Also we have T cos theta = m g and T sin theta = 9x10^9(Q^2/0.0300^2). Dividing second equation by first, we have

tan theta = {[(9x10^9)/0.0300^2]Q^2}/(7.40x10^-8x9.8) or
(7.40x9.8x10^-8)(1/4sqrt(3)) = [1*10x10^11]Q^2 or
(1.046x10^-7)/(1x10^11) = Q^2 or
1.046x10^-18 = Q^2 or Q = 1.0227x10^-9= 1.0227 nC