B. Experimental Proof of W = K (for a Varying Force) Measuring Work The varying force will be due to a spring. Use the wide spring (not the narrow silver spring). First measure the work done to stretch the spring. Attach one end of the spring to the horizontal rod mounted above the table so that the spring hangs vertically. Hang a small (m = 20 gram) on the other end of the spring and measure the distance x the spring stretches. Add more mass and