Chapter #8 Solutions - Physical Science with Modern Applications - Melvin Merken - 5th Edition

 

1. What did Joule’s experiments prove about energy? Get solution

2. Water at Niagara Falls undergoes a 160-foot drop. Would you expect a difference in the temperature of the water between the top and the bottom of the Falls? Explain. Get solution

3. A 75.0-kilogram man climbs a staircase 7.00 meters high. How much energy (in calories) does he expend? Get solution

4. If the energy in the food that a man consumes in one day, 3000 kcal, were all converted into mechanical energy, how high would it lift a 75.0-lalogram mass? Get solution

5. Explain what is meant by the conservation of energy. Get solution

6. Give an example of a device that can perform the conversion of (a) electrical energy to thermal energy; (b) mechanical energy to thermal energy; (c) chemical energy to thermal energy. Get solution

7. In highly developed countries, a person consumes approximately 3000 kilocalories per day as food. Explain what happens to this energy. Get solution

8. Which law of thermodynamics can be paraphrased as follows: “You can’t win; the best you can do is break even”? Discuss. Get solution

9. Apply the first law of thermodynamics to the motion of an automobile. Get solution

10. How are the concepts of entropy and “time’s arrow” related? Get solution

11. The first law says that we cannot get more out of a process than we put in, but the second law says that we cannot break even. Explain. Get solution

12. Which do you think has the greater entropy, 1 kg of water or 1 kg of ice? Why? Get solution

13. Give an example of a natural process in which order goes to disorder. Get solution

14. Does straightening out a room after a party violate the second law of thermodynamics? Explain. Get solution

15. The input of a heat engine is 5000 calories per cycle, and the work output is 2000 joules per cycle. What is the efficiency of the engine? Get solution

16. Could a heat engine be designed with a thermal efficiency of 100%? Explain. Get solution

17. The efficiency of an engine that obtains heat at 260°C and exhausts heat at 60.0°C is 16.0%. What is its maximum possible efficiency? Get solution

18. A steam turbine operates between the temperatures of 800°C and 20.0°C with an efficiency of 33.0%. How does its efficiency compare with the efficiency of a Carnot engine operating between the same temperatures? Get solution

19. What is the Carnot efficiency of a steam turbine working between 300°C and 40.0°C? Get solution

20. How did James Watt influence the modern world? Get solution

21. Describe what happens to the waste heat in an automobile engine that has an efficiency of 25.% Get solution

22. State some advantages and disadvantages of rotary engines over reciprocating engines. Get solution

23. How does a rocket engine differ from a turbojet engine? Get solution

24. List some favorable and adverse effects of the internal combustion engine on society. Get solution

25. A major component of an electric power plant is a steam turbine. What is the advantage of raising the temperature of the steam as much as possible? Get solution

26. What is the purpose of an automobile radiator? Get solution

27. Multiple ChoiceA. A heat engine is designed to(a) heat houses.(b) cool houses.(c) change work into heat.(d) change heat into work.B. The law of conservation of energy is expressed by the(a) first law of thermodynamics.(b) second law of thermodynamics.(c) first law of motion.(d) second law of motion.C. A mixture of salt and pepper separating into different layers when shaken violates the(a) conservation of energy.(b) conservation of momentum.(c) law of entropy.(d) principle of efficiency.D. The mechanical equivalent of heat is expressed by(a) J.(b) W.(c) H.(d) C.E. The Carnot efficiency of a diesel engine is(a) easy to attain.(b) its maximum possible efficiency.(c) 100%.(d) a measure of its thermal energy.F. For every natural process, the entropy of the universe(a) decreases.(b) is destroyed in part.(c) increases.(d) remains constant.G. The larger the thermal efficiency of a heat engine,(a) the greater the heat input.(b) the more heat output for a given heat input.(c) the greater the work output for a given heat input.(d) the larger the Carnot efficiency of the engine.H. A diesel engine(a) is a type of rotary engine.(b) operates in a four-stroke cycle.(c) is a Carnot engine.(d) has no spark plug.I. The theoretical limit for the efficiency of a cyclic heat engine is given by(a) the first law of thermodynamics.(b) entropy.(c) Carnot efficiency.(d) the work output.J. In a thermodynamic process,(a) the entropy always increases.(b) energy is conserved.(c) heat is always transferred.(d) heat flows spontaneously from a colder body to a warmer body. Get solution