Exercises The Atmosphere (page 383) 20.2 Atmospheric Pressure (pages )

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1 Exercises 20.1 The Atmosphere (page 383) 1. The energizes the molecules in Earth s atmosphere. 2. Why is gravity important to Earth s atmosphere? 3. What would happen to Earth s atmosphere without the sun? 4. Is the following sentence true or false? Like the ocean, Earth s atmosphere has a definite surface. 5. The density of the atmosphere with altitude. 6. How are the molecules that make up Earth s atmosphere like a huge pile of feathers? 7. What is the density of gas in interplanetary space? 8. Circle the letter of the most plentiful element in the universe. a. oxygen b. nitrogen c. hydrogen d. carbon 9. Circle the letter of the level below which 99% of the atmosphere is found. a. 3 kilometers b. 30 kilometers c. 300 kilometers d. 3,000 kilometers 10. Compare the thickness of Earth s atmosphere to Earth s radius. 11. Describe how the temperature of the atmosphere changes with increasing altitude Atmospheric Pressure (pages ) 12. Atmospheric pressure is caused by the of air. 13. What is the mass of air in a room that has a volume of 50 m 3? The temperature of the room is 20 C. 14. Is the following sentence true or false? Air doesn t weigh very much, no matter how much you have of it. Conceptual Physics Reading and Study Workbook 161

2 15. Consider a 1-square-meter column of air that extends up through the atmosphere. a. What is the mass of the air in the column? b. What is the weight of the air in the column? c. What pressure does the air in the column produce? 16. The average atmospheric pressure at sea level is. 17. Name three things that can cause variations in atmospheric pressure. a. b. c. 18. Measurement of changing is important to meteorologists in predicting weather The Simple Barometer (pages ) 19. What does a barometer measure? 20. Circle the letter of the word or phrase that completes the statement. The tube of a mercury barometer must be 76 cm tall. a. exactly b. less than c. approximately d. greater than 21. Under what conditions would the mercury in a barometer completely fill the tube? 22. How would a barometer differ if water were used in the tube instead of mercury? 23. Circle the letter of each statement that is true. a. The liquid in a barometer is pushed up by pressure. b. The liquid in a straw is sucked up by pressure. c. Sucking on a straw increases the air pressure in the straw. d. In an old-fashioned pump, the atmosphere pushes water from below into a pipe at the surface. 162 Conceptual Physics Reading and Study Workbook

3 20.4 The Aneroid Barometer (page 388) 24. An aneroid barometer is an instrument that measures variations in atmospheric pressure without a. 25. How does an aneroid barometer measure atmospheric pressure? 26. A(n) is an aneroid barometer calibrated to determine elevation Boyle s Law (pages ) 27. The and the are greater inside an inflated tire than outside. 28. Describe what causes the pressure exerted by air inside an inflated tire. 29. Is the following sentence true or false? If the density of air in a tire increases, the air pressure increases The figure below shows how the movement of a piston in a cylinder can affect the air inside the cylinder. Use the figure to complete the table below. Movement of Piston Downward Upward Change in the Air s Volume decreases by half decreases to a third of its original value Change in the Air s Density decreases by half Change in the Air s Pressure three times its original value a third of its original value a third of its original value Conceptual Physics Reading and Study Workbook 163

4 31. State Boyle s law in words and in an equation. a. in words: b. as an equation: 32. Why is Boyle s law important to a scuba diver who is ascending? 20.6 Buoyancy of Air (page 391) 33. The rules for buoyancy hold for both and. 34. State Archimedes principle for air. 35. Any object that is than the air around it will rise Bernoulli s Principle (pages ) 36. Is the following sentence true or false? Atmospheric pressure increases in a hurricane. 37. Consider a continuous flow of water through a pipe. Circle the letter of each statement that is true. a. The amount of water that flows past any section of the pipe changes with pipe width. b. The water will slow down in a wider part of the pipe. c. The water will speed up in a narrower part of the pipe. d. The amount and speed of the water in the pipe does not change. 38. State Bernoulli s principle. 39. Is the following statement true or false? The pressure within a fluid is different from the pressure it can exert on anything in its path that slows it down. 40. Define streamlines. 41. Streamlines that are closer together indicate a(n) in fluid speed and a(n) in the fluid s internal pressure. 164 Conceptual Physics Reading and Study Workbook

5 42. Explain how air bubbles in a fluid are related to the fluid s pressure and speed. 43. What is an eddy? 20.8 Applications of Bernoulli s Principle (pages ) 44. What happens to a sheet of paper if you hold one end and blow air across the top of it? 45. Define lift. 46. Use the figure below to explain how lift makes horizontal flight possible. 47. Is the following sentence true or false? During a strong wind, such as a tornado, the air inside a building may push the roof off. 48. Explain why passing ships run the risk of sideways collisions. 49. Is the following sentence true or false? A shower curtain billows inward when the shower is turned on full blast because air pressure inside the shower increases. Conceptual Physics Reading and Study Workbook 165