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A man standing still finds rain pouringat angle 30^(@) with vertical , whenhs starts walkingforward at a speed of 4Kmph it appers to him that rain pours vertically down. Whenhe runs attriple the speed, whatis the angleat whichrain appers to pour ? |
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Answer» Solution :Case I : When the MAN is still `V_(R)` = ACTUAL (ABSOLUTE ) velocityof rain. Case : II Whenman walksat 4kph. rain fall vertically mean horizontal component of rains.velocity= 4 `therefore V_(R) sin30^(@) = 4 rArr V_(R) = 8`  Case : III The man runsat triple the speed `V_(M) = 12kph`. we have superimposed `V_(M) ` to `V_(R) ` to get theresultant . Fromfigurewe see `TAN phi = (O.B)/(OO.) = (12-4)/(sqrt(8^(2) - 4^(2)) = (8)/(sqrt(48)) = (2)/(sqrt(3)) thereforephi = 49` andraindrop makes an angle of `49.6^(@)` in oppositedirection. 
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