When you jog, most of the food energy you burn above your basal metabolic rate (BMR) ends up as internal energy that would raise your body temperature if it were not eliminated. The evaporation of perspiration is the primary mechanism for eliminating this energy. Determine the amount of water you lose to evaporation when running for 30. minutes at a rate that uses 4.00 x 102 kcal/h above your BMR. (That amount is often considered to be the “maximum fat - burning” energy output.) The metabolism of 1.0 grams of fat generates approximately 9.0 kcal of energy and produces approximately 1.0 grams of water. (The hydrogen atoms in the fat molecule are transferred to oxygen to form water.) What fraction of your need for water will be provided by fat metabolism? (The latent heat of vaporization of water at room temperature is 2.5 x 106 J/kg.)

The rate at which a resting person converts food energy is called one’s basal metabolic rate (BMR). Assume that the resulting internal energy leaves a person’s body by radiation and convection of dry air. When you jog, most of the food energy you burn above your BMR becomes internalenergy that would raise your body temperature if it were not eliminated. Assume that evaporation of perspiration is the mechanism for eliminating this energy. Suppose a person is jogging for “maximum fat burning,” converting food energy at the rate 400 kcal/h above his BMR, and putting out energy by work at the rate 60.0 W. Assume that the heat of evaporation of water at body temperature is equal to its heat of vaporization at 100°C. (a) Determine the hourly rate at which water must evaporate from his skin. (b) When you metabolize fat, the hydrogen atoms in the fat molecule are transferred to oxygen to form water. Assume that metabolism of 1.00 g of fat generates 9.00 kcal of energy and produces 1.00 g of…

An automobile tire initially contains 0.12 kg of air at 250 kPag and 22°C. Assume that the tire does not stretched and is equipped with a pressure release valve such that the air pressure in the tire will not exceed 290 kPag, Due to running conditions the temperature in the tire reached 80°C. Determine the amount of air in grams that escapes.