The average person generates about 2500 Kcal of heat a day. How many kilowatt-hours of energy is this? If walking briskly dissipates energy at 500 W, what fraction of the day's energy does walking one hour represent? How many kilograms of water would have to be evaporated if this were the only means of heat loss? (The heat of vaporization of water at 35 degree celsius is 2400J/g).