Doughnuts: Breakfast of Champions! A typical doughnut contains 2.0 g of protein, 17.0 g of carbohydrates, and 7.0 g of fat. The average food energy values of these substances are
4.0 kcal/g for protein and carbohydrates and 9.0 kcal/g for fat.
(a) During heavy exercise, an average person uses energy at a rate of 510 kcaI/h. How long would you have to exercise to “'work off” one doughnut?
(b) If the energy in the doughnut could somehow be converted into the kinetic energy of your body as a whole, how fast could you move after eating the doughnut? Take your mass to be 60 kg, and express your answer in m/s and km/h.