A bird is about 6.5 in. long, with a thin, dark bill and a wide, white wing stripe. If the bird can fly 88 mi with the wind in the same time it can fly 72 mi against the wind when the wind speed is 2 mph, what is the rate of the bird in still air?

Question

Physics

Marianna

30 January, 18:19

A bird is about 6.5 in. long, with a thin, dark bill and a wide, white wing stripe. If the bird can fly 88 mi with the wind in the same time it can fly 72 mi against the wind when the wind speed is 2 mph, what is the rate of the bird in still air?

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Answers (1)

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Angelina Cowan · Answer 1

20.0 mph

Explanation:

Let x represent the speed in still air, and t represent the time of flight;

Speed of wind = 2 mph

When flying with the wind, it's Speed is;

x + 2

When flying against wind, it's speed is;

x - 2

distance = speed * time;

When flying with the wind, distance is;

(x+2) t = 88 ... 1

When flying against wind, distance is;

(x-2) t = 72 ... 2

Solving the simultaneous equation;

Divide equation 1 by 2

(x+2) t / (x-2) t = 88/72

(x+2) / (x-2) = 1.222

x+2 = 1.222 (x-2)

x+2 = 1.222x - 2.444

x (1.222-1) = 2+2.444

x (0.222) = 4.444

x = 4.444/0.222

x = 20.0 mph

the rate of the bird in still air is 20.0 mph