A river flows at 3 m/s and is 300 m wide . A man swing across the rivers with a velocity of 2 m/s directed always perpendicular to the flow of current . (a) How long does it take the man to cross the river ? (b) In what direction does he actually moves to cross the relative to the shore ? (c) How far down the fiver(from the starting point ) does he reach the opposite bank?

Answer

(a) 150s, (b) `tan^(-1)(2//3)` (c) `150sqrt(3)m`

Explanation

(a) `t=(300)/(2)= 150s`
(Here 2 is `bot^(ar)` velocity to the river.)
(b)
`tan thea =(2)/(3)`
`theta = tan^(-1) (2)/(3)`
(c) `x =v_(r) xx t = 3 xx 150 = 450 m`