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AP EAMCET202018 Sep 2020Evening ShiftPhysicsMotion in Two DimensionsActual

A swimmer can swim in still water with speed (v ) and the river flowing with velocity ( v 2 ). To cross the river in shortest time, he should swim making angel ( ) with the upstream. What is the ratio of the time taken to swim across in the shortest time to that in swimming across over shortest distance?

Options

  1. A( )
  2. B( )
  3. C( )
  4. D( )

Correct answer

C. ( )

Step-by-step solution

If (d ) be the width of river and ( ) be the angle made with the upstream. Therefore, angle made with normal stream (=90^ - ) Hence, by shortest time method, ( time taken, t= d v ) ...(i) By shortest distance method, ( aligned time taken, t^ & = d v (90^ - ) t^ & = d v (ii) t t^ & = d / v d / v = aligned )

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