(a) A physics lab instructor is working on a new demonstration. She attaches two identical metal balls with mass m = 0.210 g to filaments of length L as shown in the figure. A 171 Both balls have the same charge of 6.80 nC, and are in static equilibrium when 8 = 4.85. What is L (in m)? Assume the filaments are massless. m MY NOTES ASK YOUR TEACHER (b) What If? The charge on both balls is increased until each filament makes an angle of 9= 9.70 with the vertical. If both balls have the same electric charge, what is the charge (in nC) on each ball in this case? nC