Question

A girl wishes to swim across a river to a point directly
opposite as shown. She can swim at 2 m/s in still water and the
river is flowing at 1 m/s. At what angle with respect to the line
joining the starting and finishing points should she swim?​

Answer 1

Explanation:

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11th

Physics

Motion in a Plane

Relative Motion in 2 Dimension

A swimmer wishes to reach d...

PHYSICS

A swimmer wishes to reach directly opposite bank of a river, flowing with velocity 8 m/s. The swimmer can swim 10 m/s in still water. The width of the river is 480 m. Time taken by him to do so:

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ANSWER

so to reach directly opposite bank of river he has to swim at an angle where component of his velocity cancel out the flow of water so that he can go directly opposite bank of the river.

so if we assume he is swimming at an angle θ with the flow, we get

10Cosθ=8

and also 10Sinθ will be component which will help him cross the river.

so if Cosθ=0.8 then Sinθ=0.6

velocity helping in crossing the river =10×0.6=6m/s

also distance is given width=480m

time taken will be t=

6

480

=80