(Trying not to hijack James post about his awesome gun.....)
Steve, now that yer back on earth, I ran that same equation thru my calcualtor and got 38.04. Which I supoose is close enough that it probably doesnt matter. But, as I started breakng it down trying to figure it out, it occured to me maybe I didnt follow the "order of operations" when running thru the equation. But IIRC from my programming class days, Multipication and division carry the same "wieght" and in this case just work it left to right. The other thing I think my have skewed my answer is not using enough places to the right of the decimal point (I used 3.17.... cant mremember more than that...)
I did figure out a couple things on my own: the "/3" referes to the arm moving thru a 120 degree arc, and 120 is one third of 360 degrees of the circle. Still dont understand what the 2 between 18 and pi is, or how you got from 36 inches to 14.6 pounds of effort. the other thing I may not have accounted for is the inches aprt of that... does that have an influence on the arc of travel the pump arm moves thru to the energy needed?
(Edit: Wikipedia says pi is " 3.14159". Which brigns my 38.04 down to 37.69908, and thats much closer to your answer.)
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