Question

A `10 kg` boy standing in a `40 kg` boat floating on water is `20 m` away from the shore of the river. If the boy moves `8 m` on the boat towards the shore, then how far is he from the shore ? (Assume no friction between boat and water).
A. 12.0 m
B. 13.6 m
C. 12.8 m
D. 11.6 m

Answer 1

Correct Answer - B
(b) Let the boat moves a distance `x` away from shore.
Then net displacement of boy towards shore `= 8 - x`
Now apply : `m_1 x_1 = m_2 x_2`
`rArr 40 x = 10(80 - x) rArr x = 1.6 m`
Distance of boy from shore `= 20 - (8 - x) = 13.6 m`.
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