Question

A motor boat is to reach at a point `30^@` upstream on the outer side of a river flowing with velocity `5 ms^(-1)`. The velocity of motor boat with respect to water is `5(sqrt3) ms^(-1)`. The driver should steer the boat at an angle.

A. `30^(@)` up w.r.t the line of destination from the starting point
B. `60^(@)`up w.r.t normal to the bank
C. `150^(@)` w.r.t stream direction
D. none of these

Answer 1

Correct Answer - A::B::C
The velocity of motor boat is given as
`vecv_(m)=vecv_(mx)+vecv_(w)`
`rArr 5/(sin theta)=5sqrt3/(sin 120^(@)) rArr sin theta=1/2 rArr theta=30^(@)`
`:. (a),(b),( c)`