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A boat man could row his boat with a spe...

A boat man could row his boat with a speed 10 m/sec. He wants to take his boat from P to a point Q just opposite on the other bank of the river flowing at a speed 4 m/sec. He should row his boat–

A

At right angle to the stream

B

At an angle of `sin^(-1)(2/5)` with PQ up the stream

C

At an angle of `sin^(-1)(2/5)` with PQ down the stream

D

At an angle of `cos^(-1)(2/5)` with PQ down the stream

Text Solution

Verified by Experts

The correct Answer is:
B

`|V_(n) sin theta|=| overset rarr V_(r)|` `overset rarr V_(t)=` Velocity of river
`10 sin theta= 4` `overset rarr V_(B)=` Velocity of boat
`sin theta = (4)/(10)=(2)/(5)` `overset rarr V_(Br)=` Velocity of boat w.r.t. river.
`theta = sin^(-1)(2/5)`
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Knowledge Check

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