An antique pendulum clock has to be wound up every Sunday at the same time to show the correct time during the whole week. While winding up, one has to raise a weight m=5.6 kg by h=31 cm to enable the clockwork to drive the pendulum. The pendulum is of length l=64 cm and almost all its mass is located at the lower end. How much energy (on average) is dissipated during one swing?