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![[Post New]](/templates/default/images/icon_minipost_new.gif) 22 May 2008 00:36:35 IST
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equation of trajectory :
y = xtanA - gx^2/2u^2cos^2A
putting x=30,y=40...we get
u^2 = 450/{3cosAsinA - 4cos^2A}
u^2 = 90/{cosAsin(A - 53')}
u^2 = 180/{sin(2A - 53) - sin53}
for u to be minimum, denominator is to be max..
and denominator is max for 2A = 90 + 53 (find it by using simple derivative)
so, min u^2 = 180/{1 - 4/5}
min u^2 = 900
sooo, min u = 30 m/s :)
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LOKESH SARDANA,
department of Production and Industrial engineering,
Indian Institute of Technology,Roorkee.
Happiness can be found, even in the darkest of times, if one only remembers to turn on the light.
Albus Dumbledore
Harry Potter and the Prisoner of Azkaban movie
There are only two ways to live your life. One is as though nothing is a miracle. The other is as though everything is a miracle.
-- Albert Einstein
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