A boy in a wheelchair (total mass 45.0kg) wins a race with a skateboarder. He has speed 1.40 m/s at thecrest of a slope 2.00 m high and 12.4m long. At the bottom of the slope his speed is 6.40 m/s. If air resistance and rolling resistancecan be modeled as a constant friction force of 41.0 N, find thework he did in pushing forward on his wheels during the downhillride.