A 62 kg skier leaves the end of a ski-jump ramp with a velocity of 30 m/s directed 26° above the horizontal. Suppose that as a result of air drag the skier returns to the ground with a speed of 25 m/s, landing 8.8 m vertically below the end of the ramp. From the launch to the return to the ground, by how much is the mechanical energy of the skier-Earth system reduced because of air drag?