Chapter 14, Problem 81GP

Basal metabolic rate. The energy output of an animal engaged in an activity is called the basal metabolic rate (BMR) and is a measure of the conversion of food energy into other forms of energy. A simple calorimeter to measure the BMR consists of an insulated box with a thermometer to measure the temperature of the air. The air has a density of 1.29 kg/m³ and a specific heat of 1020 J/(kg·K). A 50.0 g hamster is placed in a calorimeter that contains 0.0500 m³ of air at room temperature. (a) When the hamster is running in a wheel, the temperature of the air in the calorimeter rises 1.8 C° per hour. How much heat does the running hamster generate in an hour? (Assume that all this heat goes into the air in the calorimeter. Ignore the heat that goes into the walls of the box and into the thermometer, and assume that no heat is lost to the surroundings.) (b) Assuming that the hamster converts seed into heat with an efficiency of 10%. and that hamster seed has a food energy value of 24 J/g, how many grams of seed must the hamster eat per hour to supply the energy found in part (a)?