These brain teasers get printed in newsletters around the world. In some of these places English is not the first language. I don't think anyone is doing an official translation. So I sometimes wonder if those readers having to translate it for themselves have a hard time making sense of my stories and humor. To be fair I have considered sending out the column alternately in Hindi, German, Chinese, etc., so as not to show favoritism to the native English speakers. Then I remembered that I am not really fluent in all of these languages and I don't even own an English-Chinese dictionary.
Anyway, let's get to the problem. I attended a conference on weather modeling the other day, a very interesting physics and math problem domain. These calculations are sometimes done in order to predict the path of hurricanes and tornadoes. So, after a 100 pound woman is airborne, how long does it take her to get from 0 to 30 MPH if she has a constant net horizontal accelerating force from the wind of 100 pounds(force). Obviously the wind is building during her entire flight. You can ignore wind drag and all other forces for this problem. I am using English units in order to add to the challenge, maybe metric next time.
Reply to Butch Shadwell at b.shadwell@ieee.org (email), 904-410-9751 (fax), 904-410-9750 (v), 3308 Queen Palm Dr., Jacksonville, FL 32250-2328. (http://www.shadtechserv.com) The names of correct respondents may be mentioned in the solution column.
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While attending a conference on weather modeling I got the idea for a BTC involving someone being airborne in a storm, after a 100 pound woman is airborne, how long does it take her to get from 0 to 30 MPH if she has a constant net horizontal accelerating force from the wind of 100 pounds(force)? Obviously the wind is building during her entire flight. You can ignore wind drag and all other forces for this problem. I am using English units in order to add to the challenge, maybe metric next time.
I didn't think of it at the time, but by making the net driving force equal to her weight, the problem gets very easy. We know that her mass (in slugs) times the acceleration due to gravity (32.2ft/s^2) is equal to 100 pounds of force (F = ma). So her mass, the same number of slugs mentioned above, must accelerate at 32.2ft/s^2 horizontally when a 100 pound force is applied (a = F/m). You were instructed to ignore all other forces. Since v = at and 30 mph is equal to 44ft/s, it takes 1.37 seconds to get to the specified speed. But I bet you already knew that.
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