A man weighing 180 lbf is pushing a cart that weighs 100 lbf with its contents up

Question:

A man weighing 180 lbf is pushing a cart that weighs 100 lbf with its contents up a ramp that is inclined at an angle of 108 from the horizontal. Determine the work needed to move along this ramp a distance of 100 ft considering (a) the man and (b) the cart and its contents as the system. Express your answers in both lbf·ft and Btu.