If work W is required to stretch a spring a distance x from its unstretched length, what work (in terms of W) is required to stretch the spring an ?additional? distance x?

Solution 24DQ Step 1: Consider a spring having spring constant, “k” is stretched to a distance “x” from its initial length “l”. Then, the restoring force is, F = - k x The work done would be, W = F x We should consider the magnitude of the force while calculating the work done because, the restoring force and force applied is having equal magnitude. 2 Therefore, W = kx × x = kx