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Speed of a man in water is 5 km ther, mantories to cross a vive filowing towardscast at 3km/hr of width Toom.find the Shortest time in which man crossesriver.Aut what angle from flow velocity manShould swim to reach directly opposite PointMan starts swimming forum Point A makingS3 angle with flow velocity. Find thePosition where he will reach also findthe time. |
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Answer» a. Velocity of man with respect to river water, v=5kmh−1. This is greater than the river flow velocity. Therefore, he can cross the river directly (along the shortest PATH or no drift CONDITION from flow velocity). The ANGLE of swim, θ=2π+sin−1(vu) = 90o+sin−1(vu) = 90o+sin−1(53) =90o+37o = 127o w.r.t. the river flow or 37o w.r.t. the perpendicular in upstream direction
= 52−32 =4kmh−1
t = d/ v2−u2d = 1km / 4kmh ^ −1 = 1 / 41h |
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