Motion In A Plane Ques 58
58. A boat is sent across a river with a velocity of $8 $ $km $ $h^{-1}$. If the resultant velocity of boat is $10 $ $km$ $ h^{-1}$, then the velocity of the river is
[1993]
(a) $12.8 $ $km$ $h^{-1}$
(b) $6 $ $km$ $h^{-1}$
(c) $8 $ $km$ $h^{-1}$
(d) $10 $ $km $ $h^{-1}$
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Answer:
Correct Answer: 58.(b)
Solution:
- (b) $v_r=\sqrt{v_R^{2}-v_B^{2}}$
$=\sqrt{10^{2}-8^{2}}=6 $ $km $ $h^{-1}$
BETA
