A 5-g coin is dropped from a 300-m building. If it reaches a terminal velocity of 45 m/s, and the rest of the energy is converted to heating the coin, what is the change in temperature (in C) of the coin? (The specific heat of copper is 387 J/kg/C.)
a. 9
b. 2
c. 5
d. 21
e. 0.5
[Ques. 2] A child has a temperature of 101F. If her total cross-sectional area is 2 m2, find the energy lost each second (in W) due to radiation, assuming the emissivity is 1 . (Assume the room temperature is 70F.)
a. 217
b. 180
c. 90
d. 68
e. 850
[Ques. 3] A cup of coffee is enclosed on all sides in an insulated container 1/2 cm thick in the shape of a cube 10 cm on a side. The temperature of the coffee is 95C, and the temperature of the surroundings is 21C. Find the rate of heat loss (in J/s) due to conduction if the thermal conductivity of the cup is 2 104 cal/s/cm/C.
a. 62
b. 74
c. 230
d. 160
e. 12
[Ques. 4] A slab of concrete and an insulating board are in thermal contact with each other. The temperatures of their outer surfaces are 68F and 50F. Determine the rate of heat transfer (in BTU/ft2/h) if the R values are 1.93 and 8.7 ft2/F/h/BTU, respectively.
a. 9.7
b. 2.5
c. 5.3
d. 1.7
e. 28
[Ques. 5] How much heat (in kcal) must be removed to make ice at 10C from 2 kg of water at 20C? (The specific heat of ice is 0.50 cal/g/C.)
a. 190
b. 200
c. 240
d. 210
e. 50
[Ques. 6] If 25 kg of ice at 0C is combined with 4 kg of steam at 100C, what will be the final equilibrium temperature (in C) of the system?
a. 40
b. 20
c. 60
d. 100
e. 8
[Ques. 7] How much heat (in kilocalories) is needed to convert 1.00 kg of ice at 0C into steam at 100C?
a. 23.9
b. 79.6
c. 564
d. 643
e. 720
[Ques. 8] A 300-g glass thermometer initially at 25C is put into 200 cm3 of hot water at 95C. Find the final temperature (in C) of the thermometer, assuming no heat flows to the surroundings. (The specific heat of glass is 0.2 cal/g/C.)
a. 52
b. 68
c. 89
d. 79
e. 36
[Ques. 9] A 5-kg piece of lead (specific heat 0.03 cal/g/C) having a temperature of 80C is added to 500 g of water having a temperature of 20C. What is the final equilibrium temperature (in C) of the system?
a. 79
b. 26
c. 54
d. 34
e. 20
[Ques. 10] A 5-gallon container of water (approximately 20 kg) having a temperature of 212F is added to a 50-gallon tub (approximately 200 kg) of water having a temperature of 50F. What is the final equilibrium temperature (in C) of the mixture?
a. 54
b. 36
c. 18
d. 66
e. 14
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