Physics - Kinematics Question with Solution | TestHub

PhysicsKinematicsRelativeMedium2 minQB

PhysicsMediumnumerical

Passage / Comprehension

A swimmer wishes to cross a river from A. If he swims perpendicular to the flow of the river, he takes 10 min to cross the river and reaches point C, at a distance of 120 m downstream from the opposite point B. If he swims at an angle $α$ such that he directly reaches B, it takes him 12.5 minutes to reach the other end. (Assuming he crosses the river with constant velocity)

Find speed of river flow in m/min :

Answer:

12.00

Solution:

$\frac{d}{v} = 10 min .$ $u \times 10 min . = 120 m$

$\frac{v ^{2} - u ^{2}}{d} = 12.5 min .$

$u = 12 m / min .; v = 20 m / min .; d = 200 m$

$200 m = 0 \times t + \frac{1}{2} \times 1 \times t^{2}$

$t = 20 sec . = \frac{1}{3} min .$

Stream:JEESubject:PhysicsTopic:KinematicsSubtopic:Relative

⏱ 2mℹ️ Source: QB

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