The latent heat of vaporization of H20 at body temperature (37C) is 2.42 x 106 J/kg. To cool the body of a 87.9-kgjogger [average specic heat capacity = 3500 J/(kg C)] by 2.32 C, how many kilograms of water in the form of sweat have to be evaporated? Number n Units kg V Multiple-Concept Example 8 reviews the approach that is used in problems such as this. A person eats a dessert that contains 190 Calories. (This "Calorie" unit, with a capital C, is the one used by nutritionists; 1 Calorie = 4186 J. See Section 12.7.) The skin temperature of the person is 38 C and that of her environment is 20 C. The emissivity of her skin is 0.66 and its surface area is 1.0 m2. How many hours would it take her to emit a net radiant energy from her body that is equal to the energy contained in this dessert? Heat from environment Heat from To person\fIn an electrically heated home, the temperature of the ground in contact with a concrete basement wall is 12.0 0C. The temperature at the inside surface of the wall is 21.9 0C. The wall is 0.15 m thick and has an area of 7.5 m2. Assume that one kilowatt hour of electrical energy costs $0.10. How many hours are required for one dollar's worth of energy to be conducted through the wall? Number n Units v