College Physics 10th Edition by Raymond Serway,Chris Vuille

Exercise 15

Two 2.0-g spheres are suspended by 10.0-cm-long light strings (Fig. P15.57). A uniform electric field is applied in the x -direction. If the spheres have charges of 5.0 × 10 8 C and +5.0 × 10 8 C, determine the electric field intensity that enables the spheres to be in equilibrium at = 10°.