68. Following vigorous exercise, the body temperature of an 80.0 kg person is 40.0 °C. At what rate in watts must the person transfer thermal energy to reduce the body temperature to 37.0 °C in 30.0 min, assuming the body continues to produce energy at the rate of 150 W? (1 watt = 1 joule/second or 1 W = 1J/s) 69. In a study of healthy young men¹, doing 20 push-ups in 1 minute burned an amount of energy per kg that for a 70.0-kg man corresponds to 8.06 calories (kcal). How much would a 70.0-kg man's temperature rise if he did not lose any heat during that time? 57. Most cars have a coolant reservoir to catch radiator fluid that may overflow when the engine is hot. A radiator is made of copper and is filled to its 16.0-L capacity when at 10.0 °C. What volume of radiator fluid will overflow when the radiator and fluid reach a temperature of 95.0 °C, given that the fluid's volume coefficient of expansion is 8 = 400 × 10-6/°C? (Your answer will be a conservative estimate, as most car radiators have operating temperatures greater than 95.0 °C).

68. Following vigorous exercise, the body temperature of an 80.0 kg person is 40.0 °C. At what rate in watts must the person transfer thermal energy to reduce the body temperature to 37.0 °C in 30.0 min, assuming the body continues to produce energy at the rate of 150 W? (1 watt = 1 joule/second or 1 W = 1J/s) 69. In a study of healthy young men¹, doing 20 push-ups in 1 minute burned an amount of energy per kg that for a 70.0-kg man corresponds to 8.06 calories (kcal). How much would a 70.0-kg man's temperature rise if he did not lose any heat during that time? 57. Most cars have a coolant reservoir to catch radiator fluid that may overflow when the engine is hot. A radiator is made of copper and is filled to its 16.0-L capacity when at 10.0 °C. What volume of radiator fluid will overflow when the radiator and fluid reach a temperature of 95.0 °C, given that the fluid's volume coefficient of expansion is 8 = 400 × 10-6/°C? (Your answer will be a conservative estimate, as most car radiators have operating temperatures greater than 95.0 °C).

Principles of Physics: A Calculus-Based Text

5th Edition

ISBN:9781133104261

Author:Raymond A. Serway, John W. Jewett

Publisher:Raymond A. Serway, John W. Jewett

Chapter17: Energy In Thermal Processes: The First Law Of Thermodynamics

Section: Chapter Questions

Problem 58P

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One way to cool a gas is to let it expand. When a certain gas under a pressure of 5.00 106 Ha at 25.0C is allowed to expand to 3.00 times its original volume, its final pressure is 1.07 106 Pa. (a) What is the initial temperature of the gas in Kelvin? (b) What is the final temperature of the system? (See Section 10.4.)
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Under what circumstances would you expect a gas to behave significantly differently than predicted by the ideal gas law?
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