College Physics 10th Edition by Raymond Serway,Chris Vuille

Exercise 22

Two identical metal blocks resting on a frictionless horizontal surface are connected by a light metal spring having constant k = 100 N/m and unstretched length Li = 0.400 m as in Figure P15.14a. A charge Q is slowly placed on each block causing the spring to stretch to an equilibrium length L = 0.500 m as in Figure P15.14b. Determine the value of Q , modeling the blocks as charged particles.