Question

Pls pls answer it fast ....
Its very urgent...
A bird....................wind

Answer 1

Greetings,
The answer to your question is typed below ↓
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For this problem we use relative velocity concept..

Firstly -
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Given:

time (1)  : 2 h 30 min  ---->      9000 sec
time (2)  : 4 h 30 min  ---->    16200 sec
distance :        45 km  ---->    45000 m
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Velocity of bird with respect to wind (flying in the same direction) [Vbw]
= Velocity of bird [Vb] - Velocity of wind [Vw] 

∴ Vb = Vbw + Vw        ----- 1

Velocity of bird with respect to wind (flying in the opposite direction) [Vbw]

∴ Vb = Vbw - Vw     ----- 2

= Velocity of bird [Vb] - Velocity of wind [Vw] 

Time (t1) = distance (d) ÷ (Vbw + Vw)
Time (t2) = distance (d) ÷ (Vbw - Vw)
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Using the above formulae we get equations 1 & 2.

t1 = d / (Vbw + Vw)
9000 = 45000 / (Vbw + Vw)
∴Vbw + Vw = 5    ------------ (i)

and similarly

16200 = 45000/ (Vbw-Vw)
∴ Vbw - Vw = 25/9

We then take simultaneous equations with (i) and (ii) :

Vbw + Vw = 5
Vbw -  Vw = 25/9

Solving, we get

Vbw = 3.88 m/s
&
Vw =  1.11 m/s

And finally

as Vb = Vbw + Vw

Velocity of Bird in still air = 5 m/s 
And
Speed of wind = 1.11 m/s
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P.S: Enjoy ;)