View Full Version : Another Physics problem.
KW4MW
12-06-2005, 03:47 AM
Some of you have heard this one before and many of the answers can be quite amusing. #Give it your best shot.
A student is failing Physics and the professor gives him one last chance to make a passing grade. #
He gives the student a barometer and tells him to use it to measure the height of the tallest building in town. #
How does the student use the barometer to solve the problem?
N4AUD
12-06-2005, 03:53 AM
He drops it off the building an measures how much time it takes to fall, allowing him to calculate the height of the building. Or he drops the professor off thereby delaying the failure of the class until a replacement is found.
I really don't know.
WA5KRP
12-06-2005, 04:14 AM
Mark the length of a shadow cast by the barometer and at the same time mark the length of the shadow cast by the skyscraper. Measure the two sets of marks, determine the ratio, and multiply the height of the barometer by that ratio.
Or you could put the barometer in your livingroom and go check county records for building permits.
WA5KRP
Texas
Get justfar enough away from the building so that the barometer held at arm's length has the same apparent height as the building. Measure your arm's length and then measure the distance to the building. The ratio of distance will equal the ratio of the building's height to the barameter's height.
Take barometer to pawn shop, take 'loan' to Lowe's, buy a tape measure, measure building, return tape measure to Lowe's, get refund, go to bar, get hammered on refund money, submit answer, pass, get a real job........
WA5KRP
12-06-2005, 04:37 AM
Quote[/b] (al2i @ Dec. 05 2005,22:21)]The ratio of distance will equal the ratio of the building's height to the barameter's height.
Get your own ratio! That's mine.
WA5KRP http://deephousepage.com/smilies/fight.gif
Texas
N0KLT
12-06-2005, 04:48 AM
Personally, I liked KRP's 2nd idea of checking the building permits for the height. Somewhere, in some records, someplace the height has to be mentioned.
Quote[/b] (WA5KRP @ Dec. 05 2005,21:37)]Quote[/b] (al2i @ Dec. 05 2005,22:21)]The ratio of distance will equal the ratio of the building's height to the barometer's height.
Get your own ratio! That's mine.
WA5KRP http://deephousepage.com/smilies/fight.gif
Texas
You're addled by hours of searching through musty records.
WA5KRP
12-06-2005, 05:57 AM
Quote[/b] (al2i @ Dec. 05 2005,22:59)]You're addled...
http://deephousepage.com/smilies/tapedshut.gif OMG! #My wife is posing as AL2I!
WA5KRP http://deephousepage.com/smilies/hidesbehindsofa.gif
Bombshelter, Texas
Another really easy way to measure the building would be to take a small, Texas building that is the same height as an Alaskan Barometer, and simply stand the barometer up against the building to verify that the building is indeed, pathetically puny.
http://www.davemcgraw.com/Images/towerbarometer.gif
Unless your call area is a 5, just use the standard formula.
http://www.davemcgraw.com/Images/barf2.gif
If the answers are to be graded, we need some way to obfuscate the test results on these sorts of things so that the area-5 callsigns do not suffer from self-esteem issues. Physics is hard for area-5 callsigns, and we can certainly see why:
http://www.davemcgraw.com/Images/callareaiq.gif
KF0RT
12-06-2005, 03:11 PM
The real answer:
Go to the building superintendent: "I'll give you this barometer if you'll tell me how tall the building is."
73, Rob
K9STH
12-06-2005, 03:24 PM
Considering the the "olde tyme" altimeters in aircraft actually worked from barametric pressure there is a formula that allows the pressure to be taken at the base of the building and then on the roof of the building and then the height can be calculated.
However, the "shadow method" would be as accurate, maybe even more accurate, than measuring the barametric pressure.
Glen, K9STH
K8ERV
12-06-2005, 03:41 PM
Too tough !! I would just rather flunk (but I do carry an aircraft altimeter in my car-- I live in the mountains)
TOM K8ERV Montrose Colo
K8ERV
12-06-2005, 03:47 PM
Guess, the Prof probably doesn't know---
TOM K8ERV Montrose Colo
kl7aj
12-06-2005, 05:50 PM
Quote[/b] (al2i @ Dec. 06 2005,02:55)]Unless your call area is a 5, just use the standard formula.
http://www.davemcgraw.com/Images/barf2.gif
Isn't avocado's number what they make guacamole out of?
WA5KRP
12-06-2005, 06:27 PM
http://www.davemcgraw.com/Images/barf2.gif
With a column of mercury and your average thermometer, you should be able to determine altitude, give or take a hundred meters.
WA5KRP
Texas
W2ILP
12-06-2005, 10:37 PM
Since a barometer can be used as an altimeter the solution seems simple. Measure the barametric pressure at the base of the building, then quickly run up to the roof of the building (before the weather can change) and measure the barometric pressure there. You now will find the difference in barametric pressure and from this you can caculate the difference in altitude which is equal to the height of the building.
Simple avionic altimeters use barametric pressure analog devices. Radio towers provide pilots with barametric presure at airfields in different WX conditions, which differ from sea level pressure.
This is used as a limited reference. Better avionic altimeters are RADAR altimeters, which can provide much better accuracy than barometric types.
w2ilp (Instrumentation's Lofty Pressure)
KF0RT
12-07-2005, 12:21 AM
No cheating now...
Snopes barometer page. (http://www.snopes.com/college/exam/barometer.asp)
95 ways to do this. (http://www.umu.man.ac.uk/hiking/people/physics/barometer.html)
Sadly, I'm still lost on Heather's problem.
73, Rob
Quote[/b] (al2i @ Dec. 06 2005,02:32)]If the answers are to be graded, we need some way to obfuscate the test results on these sorts of things so that the area-5 callsigns do not suffer from self-esteem issues. Physics is hard for area-5 callsigns, and we can certainly see why:
http://www.davemcgraw.com/Images/callareaiq.gif
I like this chart.............I don't know if it is correct, but I like it.
K(SEVEN)FE
I had the same problem when I was in college in 1965. The answer I gave at that time was to lower yourself down the building by rope. As you go down flip the barometer over and over end to end to get the number of barometer lengths down the side of the building. Multiplying this number times the length of the barometer gives your the answer. When the class attendance dropped, the prof. would give this as a pop quiz to punish the other absent students. He has another question he used also. It was list the different ways to use a brick to kill a roach. Rude Goldberg ruled during that question.
KD6NIG
12-07-2005, 07:38 PM
Quote[/b] (KE7DLG @ Dec. 06 2005,09:50)]Quote[/b] (al2i @ Dec. 05 2005,21:32)]If the answers are to be graded, we need some way to obfuscate the test results on these sorts of things so that the area-5 callsigns do not suffer from self-esteem issues. #Physics is hard for area-5 callsigns, and we can certainly see why:
http://www.davemcgraw.com/Images/callareaiq.gif
For some reason I am really liking your chart. Must have something to do with that area 7 line being higher than the building being measured. #http://www.qrz.com/iB_html/non-cgi/emoticons/biggrin.gif
I'm shocked that area 6 didn't read lower, considering most people's sentiments about the people in Californy....
kb9lei
12-10-2005, 01:35 AM
How about tying a string to the barometer and dropping it over the side of bulding and then measuring the string.
But, then again, that is BFTI method. (Brute Force-Total Ignorance).
{I've cut the board three times and it's STILL too short.}
KA4DPO
12-10-2005, 01:40 AM
Quote[/b] (kl7aj @ Dec. 06 2005,10:50)]Quote[/b] (al2i @ Dec. 06 2005,02:55)]Unless your call area is a 5, just use the standard formula.
http://www.davemcgraw.com/Images/barf2.gif
Isn't avocado's number what they make guacamole out of?
WRONG. That's how many Avocados are IN the guacamole... Sheesh.
n0jaa
12-10-2005, 01:49 AM
If the barometer is accurate enough, measure the barometric pressure at the base of the building, and again at the top of the building.
I wish I could remember the formula, but the difference in the two pressures should give you the altitude, or the difference between the two points and give you the height of the building.
I want to say the formula is P=M/V but I don't remember if that is the correct formula.
Paul, N0JAA.