A boy `(mass of 40 kg)` is standing at one end of a boat (mass of 60 kg) in still water. The length of the boat is `10 m` and the boy takes `2s` to reach at other end of boat moving with constant speed. Assuming no friction between the boat and the water.
(i) The distance covered by the boat is `4 m`
(ii) The distance covered by the boy with respect to the ground is `6 m`.
(iii) The velocity of the boy with respect to the ground is `lt 5 m//s`
(iv) The velocity of the boy is `3 m//s`

Options

A. `(i) ,(ii)`
B. `(ii) ,(iii)`
C. `(i),(ii),(iii)`
D. all options are correct

Answer

D

Explanation

Let `d` be the distance covered by the boat
`40(10 -d) = 60 d rArr d = 4 m`
Distance covered by the boy with respect to the ground is
`10 - d = 6 m`
Velocity of the boy w.r.t. the ground is
`(6)/(2) = 3 m//s`