1. Gerald Gangaway
On a nice winter day at the South Pole, the temperature rises to -46°F. What is the approximate temperature in degrees Celsius?
°C
2. A copper vat is 15 m long at room temperature (20°C). How much longer is it when it contains boiling water at 1 atm pressure?
3. An aluminum wing on a passenger jet is 31 m long when its temperature is 18°C. At what temperature would the wing be 6 cm (0.06 m) shorter?
4. Air in a balloon does 31 J of work while absorbing 97 J of heat. What is its change in internal energy?
5. A bottle containing 9 kg of water at a temperature of 16°C is placed in a refrigerator where the temperature is kept at 1°C. How much heat is transferred from the water to cool it to 1°C?
6. A 0.09kg lead bullet traveling 228 m/s strikes an armor plate and comes to a stop. If all of the bullet's energy is converted to heat that it alone absorbs, what is its temperature change?
7. One cubic meter of water (see Table 4.4 for the mass density of water) flowing over the Albright Falls in Yellowstone National Park drops 79 m. If all of the water's potential energy is converted to kinetic energy at the bottom of the falls and the kinetic energy goes to heat the water, what is the temperature increase of the water?
°C
8. What is the maximum efficiency that a heat engine could have when operating between the normal boiling and freezing temperatures of water?
%
9. A proposed ocean thermalenergy conversion (OTEC) system is a heat engine that would operate between warm water (21°C) at the ocean's surface and cooler water (3°C) 1,630 m below the surface. What is the maximum possible efficiency of the system? Enter your answer accurate to two decimal places.
%
10. What is the significance of absolute zero?
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11. What happens to the atoms and molecules in a substance as its temperature increases?
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12. Air molecules in a warm room (27°C = 300 K) typically have speeds of about 500 m/s (1,100 mph). Why is it that we are unaware of these fast moving particles continuously colliding with our bodies?
The mass of an air molecule is so miniscule that its momentum and kinetic energy are too small to be evident in the collision with a human body.
The size of an air molecule is extremely small, so its momentum and kinetic energy are not efficiently transferred to our bodies when the collisions with a human body occur.
The density of the warm air is so low that the air molecules tend to miss our bodies.
Because the air molecules are everywhere around us they constantly collide with our bodies from all directions. The effect of these collisions tend to cancel out.
13. What is unusual about the behavior of water below the temperature of 4°C?
Within the range of 0°C to 4°C the specific heat of water is halved when the temperature decreases, whereas the specific heat of most substances is doubled.
Within the range of 0°C to 4°C the specific heat of water doubles when the temperature decreases, whereas the specific heat of most substances is halved.
Within the range of 0°C to 4°C water expands when the temperature decreases, whereas most substances contract. Within the range of 0°C to 4°C water contracts when the temperature decreases, whereas most substances expand.
14. Is it possible to compress air without causing its internal energy to increase?
Yes No
If so, how?
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