a) From the known value of atmospheric pressure at the surface ofthe Earth, estimate the total number of air molecules in theEarthâs atmosphere. (Hint: Disregard air motion and consider staticequilibrium on the atmosphere. The atmosphere presses on the groundand by Newtonâs 3rd law there is a reaction force acting on theair. What is balancing this force?)
b) During certain seasons, strong winds call Chinooks blow from thewest across the eastern slopes of the Rockies and downhill intoDenver. Although the winds come from mountains where thetemperature is low, the temperature in Denver can climb 20 °Cwithin a few minutes after the Chinook wind arrives. Similar windsoccur in the Alps and in Southern California. Explain why thetemperature of the Chinook wind rises as it descends the slopesrapidly? (The answer to this is key to solving the numerical partof the problem, if the air moves very quickly then heat transferinto and out of the air can be neglected in the firstapproximation) Suppose the wind comes from Grays Peak (80 km westof Denver, elevation 4350 m) to Denver (elevation 1630 m) and theatmospheric condition at Grays Peak is -15.0 °C and 5.60 x 10^4 Papressure while the conditions in Denver before the wind arrives is2.0 °C and 8.12 x 10^4 Pa. By how many degrees C will thetemperature in Denver rise when the Chinook arrives? (Hint: Adetailed discussion of the physics involved in the Chinook windscan be found at http://en.wikipedia.org/wiki/Chinook_wind)
a) From the known value of atmospheric pressure at the surface ofthe Earth, estimate the total number of air molecules in theEarthâs atmosphere. (Hint: Disregard air motion and consider staticequilibrium on the atmosphere. The atmosphere presses on the groundand by Newtonâs 3rd law there is a reaction force acting on theair. What is balancing this force?)
b) During certain seasons, strong winds call Chinooks blow from thewest across the eastern slopes of the Rockies and downhill intoDenver. Although the winds come from mountains where thetemperature is low, the temperature in Denver can climb 20 °Cwithin a few minutes after the Chinook wind arrives. Similar windsoccur in the Alps and in Southern California. Explain why thetemperature of the Chinook wind rises as it descends the slopesrapidly? (The answer to this is key to solving the numerical partof the problem, if the air moves very quickly then heat transferinto and out of the air can be neglected in the firstapproximation) Suppose the wind comes from Grays Peak (80 km westof Denver, elevation 4350 m) to Denver (elevation 1630 m) and theatmospheric condition at Grays Peak is -15.0 °C and 5.60 x 10^4 Papressure while the conditions in Denver before the wind arrives is2.0 °C and 8.12 x 10^4 Pa. By how many degrees C will thetemperature in Denver rise when the Chinook arrives? (Hint: Adetailed discussion of the physics involved in the Chinook windscan be found at http://en.wikipedia.org/wiki/Chinook_wind)
