Question

Topic: Vectors
A river 500m wide flows at a rate of 4km/h. A swimmer who can swim at 8km/h in still water, wishes to cross the river straight.
(i) Along what direction must be strike?
(ii) what should be his resultant velocity?
(iii) what is the time taken for crossing the river?
pls explain the answer with a reference diagram!
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Answer 1

Explanation:

Let the angle between the swimmer and the perpendicular to the flow of river is θ with the perpendicular to the flow of river and time to cross the river is t

(i)The direction is given as,sinθ= 5/10

θ=30°

(ii)The resultant velocity is given as,V=Vs cos30∘

cos30∘ =10cos30∘

=10cos30∘ =8.66km/h

(iii)Displacement in vertical direction is given as,(Vs cosθ)t=800×10^−3

−3 (10cos30∘)t=800×10^−3

−3 t=0.092s

t=0.092st=5.5min

hope it will help u ✌️

Answer 2

Answer:

A swimmer who can swim at 10kmh−1 in still water, wishes to cross the river straight. (i) Along what direction must he strike? (ii) What should ...