SOLUTION: A man wishes to crossa river perpendicularly.in still water, he takes 4 min to cross the river, but in flowing river he takes 5 minutes.if the river is 100 meters wide,then the vel

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Question 902944: A man wishes to crossa river perpendicularly.in still water, he takes 4 min to cross the river, but in flowing river he takes 5 minutes.if the river is 100 meters wide,then the velocity of the flowung water of the river is
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
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A man wishes to cross a river perpendicularly.in still water, he takes 4 min to cross the river, but in flowing river he takes 5 minutes.
if the river is 100 meters wide, then the velocity of the flowing water of the river is:
:
Distance varies directly with time
Find speed of the man in the water
100/4 = 25 meters/min
let v = the velocity of the water in meters/min
:
Use pythag:
100^2 + (5v)^2 = (5*25)^2
10000 + 25v^2 = 15625
25v^2 = 15625 - 10000
25v^2 = 5625
v^2 = 5625/25
v^2 = 225
v = sqrt%28225%29
v = 15 m/min velocity of the river