Chapter 21, Problem 21.63P

CP Two small spheres with mass m = 15.0 g are hung by silk threads of length L = 1.20 m from a common point (Fig. P21.62). When the spheres are given equal quantities of negative charge, so that q₁ = q₂ = q, each thread hangs at θ = 25.0° from the vertical, (a) Draw a diagram showing the forces on each sphere. Treat the spheres as point charges, (b) Find the magnitude of q. (c) Both threads are now shortened to length L = 0.600 m, while the charges q₁ and q₂ remain unchanged. What new angle will each thread make with the vertical? (Hint: This part of the problem can be solved numerically by using trial values for θ and adjusting the values of θ until a self-consistent answer is obtained.)