Exercício lei de Coulomb | Halliday, Resnick vol 4 - Questão 47

42 In Fig. 21-39, two small conducting spheres of the same mass m and the same charge q are suspended by insulating threads of length L. Assume that the angle θ is so small that the approximation tan θ ≈ sin θ can be used. (a) Show that the equilibrium distance between the spheres is given by (b) If L = 120 cm, m = 10 g, and x = 5.0 cm, what is the value of |q|?