A river is flowing due east with a speed 3m/s. A swimmer can swim in still water at a speed of 4 m/s .
(a) If swimmer starts swimming due north, what will be his resultant velocity (magnitude and direction)?
(b) If he wants to start from point A on south bank and reach opposite point B on north bank,
(a) Which direction should he swim?
(b) What will be his resultant speed?
(c) From two different cases as mentioned in (a) and (b) above, in which case will he reach opposite bank in shorter time?

A river is flowing due east with a speed 3m/s. A swimmer can swim in still water at a speed of 4 m/s .
(a) If swimmer starts swimming due north, what will be his resultant velocity (magnitude and direction)?
(b) If he wants to start from point A on south bank and reach opposite point B on north bank,
(a) Which direction should he swim?
(b) What will be his resultant speed?
(c) From two different cases as mentioned in (a) and (b) above, in which case will he reach opposite bank in shorter time?

-
1 Answer
-
This is a Long Answer Type Question as classified in NCERT Exemplar
Explanation – speed of river Vr= 3m/s
Speed of swimmer Vs= 4m/s
(a) when swimmer starts swimming due north then its resultant velocity
V=
tan so ’N
(b) to reach at point B resultant velocity will be
V=
tan
(c) time taken by swimmer t =d/v= d/4s
in case b time taken by swimmer to cross the river
t1=d/v=d/
so t
1
Similar Questions for you
Please find the solution below:
after 10 kicks,
v? = 3tî v? = 24cos 60°î + 24sin 60°? = 12î + 12√3?
v? = v? – v? = (12 – 3t)î + 12√3?
It is minimum when 12 - 3t = 0 ⇒ t = 4sec
ω = θ² + 2θ
α = (ωdω)/dθ = (θ² + 2θ) (2θ + 2)
At θ = 1rad.
ω = 3rad/s and α = 12rad/s²
a? = αR = 12 m/s² a? = ω²R = 9 m/s² A? = √ (a? ² + a? ²) = 15 m/s²
a? = v? ²/4r
a_A? = (v? ²/r²) × r = v? ²/r
a_A = 3v? ²/4r
Taking an Exam? Selecting a College?
Get authentic answers from experts, students and alumni that you won't find anywhere else
Sign Up on ShikshaOn Shiksha, get access to
- 65k Colleges
- 1.2k Exams
- 688k Reviews
- 1800k Answers