Date Due: Friday, 22 September 2000
The total maximum points were 50. Point distribution for each question noted below.
(5 pts - 1 each)
1 atmosphere of pressure is equivalent to:
76.0 centimeters of mercury 14.7 (or 15) pounds per square inch (psi) 1013.25 (1000) millibar (mb) 34 feet of water
|
1b. The lowest recorded sea level corrected pressure in
the world was ________. [Please include units!]
| Lowest pressure: 870 mb = 25.68 inches of mercury |
| Highest pressure: 1083.8 mb = 32.01 inches of mercury |
| The range: Range = (High - Low)
= (1083.8 - 870) mb = 214 mb =(32.01 - 25.68) in = 6.33 in of mercury |
1c. What is the weight exerted by the atmosphere upon the flat,
horizontal roof of a 25 foot by 50 foot building? [Assume standard sea
level conditions; English units may be used here]. Clearly show your
work for partial credit! {Please include units!]
| Weight = Pressure x area
Pressure = 15 pounds per square inch (approx.) Area = 25 ft x 50 ft = 1250 sq. ft. Since 1 sq. ft. = 144 sq. in. (count them - since 12 inches on each side of the square), then 1250 sq. ft. = 1500 x 144 = 180,000 sq. inches. Then: Weight = 15 lb per sq. in x 180,000 sq. in. = 2,700,000 lb or 1350 ton (If 14.7 psi were used, the weight would be 2,646,000 lb or 1323 ton) Note that units check too! While this answer may sound large, the roof does not collapse from the weight exerted by the atmosphere since the air pressure is pushing on the roof in all directions. |
1d. A football fan brought an aneroid barometer to Mile High
Stadium in Denver (elevation of 1 mile) and made a reading of 835 mb. What
would be the approximate sea level corrected pressure if we assumed that
the pressure decreases at approximately 1 mb per 10 meters ascent through
the atmosphere? Clearly show your work for partial credit! {Please
include units!]
| Mile High Stadium in Denver is 5280 ft above mean sea level (MSL),
or 1600 m MSL.
Since the air pressure is assumed to decrease at a rate of 1 mb per 10 m, the pressure at the stadium should be 160 mb less than at the mean sea level directly below the stadium. Because the observed station (or in this case, stadium) pressure was 835 mb, by descending to sea level, the pressure would increase, or at the stadium would be [840 + 160] mb or 995 mb. |
How does this sea level pressure that you calculated compare with the
standard sea level pressure?
| The sea level pressure below Denver on this particular day (995 mb) is slightly less to a typical value of sea level pressure (1000 mb) and it is 18 mb less than standard sea level pressure (1013 mb). |
1e. Convert the following temperature readings:
| 41° F = 5° C = 278 K
-40° C = -40° F = 233 K 258 K = -15° C = 5° F Note: Be careful of signs! If the negative sign does not
appear in your answer where appropriate,
|
1f. The record highest temperature for Madison, WI was 107°F
(41.7°C) on 14 July 1936, while the record low was -37°F (-38.3°C)
on 30 Jan 1951. What is the range of Madison's extreme temperatures?
| Range = (High - Low) = 107° F - (-37)° F = 144° F. |
|
|
|
|
|
| United States | 134° F or
56.7° C |
-79.8° F or
-62.1° C (includes Alaska) -69.7° F or
|
213.8° F or
118.8° C (includes Alaska) 203.7° F or
|
| World | 136° F or
57.8° C |
-129° F or
-89.4° C |
265° F or
147.3° C |
1h. The National Weather Service at Madison reported the following
information for individual days during this past January. The "normal"
high and low temperatures for these days are also included and represent
the 30 year averages for the 1961-1990 climatological interval.
|
|
Average Temperature |
Average Temperature |
| 18 Jan 2000 |
|
|
|
|
|
|
i.) Actual Heating Degree Day Units:
| HDDU = [65° F - Average daily temperature] |
| 18 Jan 2000: 65° F - 20° F = 38 HDDU |
| 21 Jan 2000: 65° F - 1° F = 64 HDDU |
| 9 Jan: 65° F - 15° F = 50 HDDU |
| 11 Jan: 65° F - 15° F = 50 HDDU |
| Since 21 Jan 2000 was a day that was cold (daily average was +1° F) or "below normal" temperature-wise, 64 HDDU were accumulated as compared to the "normal" of 50 HDDU. Thus, more energy than normal would have to be consumed to heat your house on that day. However, three days earlier on 18 Jan 2000 the daily average of 27°F was above "normal" meaning less heat than normal would be needed, since 38 HDDU were accumulated as compared with the typical 50 HDDU. |
URL Address: aos100/homework/f00hmk01a.html
|
Homework Instruction Page |
Home Page |
Home Page |