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The speed of a swimmer in still water is...

The speed of a swimmer in still water is 20 m//s. The speed of river water of river water is 10 m//s and due east. If he is standing on the south bank and wishes to cross the river along the shortest path the angle at which he should make his stroke w.r.t. noth is given by :-

A

`30^(@)` west

B

`0^(@)`

C

`60^(@)` west

D

`45^(@)` west

Text Solution

Verified by Experts

The correct Answer is:
A
`V_(vc)=20"m/s"`
`V_(RO)=10"m/s"`
For shortest path
`overset rarr V_(SG)+ overset rarr V_(aci)=overset rarr V_(SR).`

Form vector triangle :-
`sin theta=|overset rarr V _(RO)/(overset rarr V_(SG))|`
`sin theta =(10)/(20)`
`sin theta (1)/(2)=0 = 30^(@) "west"`
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