By how much is the energy stored in a Hooke's law spring increased when its stretch is increased from 4.00 cm to 8.00 cm?
a. 100
c. 300
b. 200
d. The correct answer is not given.
[Ques. 2] The efficiency of a Carnot engine operating between 100C and 0C is most nearly:
a. 7.
c. 27.
b. 15.
d. 51.
[Ques. 3] The SI units for k, the spring constant, are equivalent to:
a. J
c. kg / s2
b. J / N
d. none of the above
[Ques. 4] Suppose a power plant uses a Carnot engine to generate electricity, using the atmosphere at 300 K as the low-temperature reservoir. Suppose the power plant produces an amount of electricity with the hot reservoir at 500 K during Day One and then produces the same amount of electricity with the hot reservoir at 600 K during Day Two. The thermal pollution was:
a. greatest on Day One.
c. the same on both days.
b. greatest on Day Two.
d. zero on both days.
[Ques. 5] An amount of work equal to 3.0 J is required to compress the spring in a spring-gun. What is the launch speed of a 15 g marble?
a. 14 m/s
c. 18 m/s
b. 15 m/s
d. 20 m/s
[Ques. 6] When gasoline is burned, it gives off 46,000 J/g of heat energy. If an automobile uses 13.0 kg of gasoline per hour with an efficiency of 18, what is the average horsepower output of the engine? (1 hp = 746 W)
a. 47 hp
c. 67 hp
b. 110 hp
d. 40 hp
[Ques. 7] A 2000-kg ore car rolls 50.0 m down a frictionless 10.0 incline. If there is a horizontal spring at the end of the incline, what spring constant is required to stop the ore car in a distance of 2.00 m?
a. 340 kN/m
c. 1700 kN/m
b. 68.1 kN/m
d. 85.1 kN/m
[Ques. 8] In which system is heat usually transferred from the cooler part to the warmer part?
a. a stove as it heats up water
b. a refrigerator that is running
c. an electric fan that is running
d. none of the above, because it is impossible to transfer heat in this manner
[Ques. 9] Which of the following is not true about potential energy?
a. Potential energy is stored energy.
c. Potential energy is a scalar quantity.
b. Potential energy is related to position.
d. Potential energy has direction.
[Ques. 10] During each cycle of operation a refrigerator absorbs 45 cal from the freezer compartment and expels 85 cal to the room. If one cycle occurs every 8.0 s, how many minutes will it take to freeze 500 g of water, initially at 0C? (Lv = 80 cal/g)
a. 800 min
c. 120 min
b. 4400 min
d. 150 min
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