Question

The distance from Parrot Point Airport to the Ivy Cliffs is 291 miles at and angle of 9.1 degrees northeast. There is a wind blowing southeast at 25 miles per hour. You want to make this trip in 3 hours by flying straight there. At what speed* and heading should you fly?

Answer 1

The flight speed should be 84.79 miles per hour at angle of 22.92° Northeast

Explanation:

The given information are;

The distance from Parrot Point Airport to Ivy Cliffs = 291 miles

The direction from Parrot Point Airport to Ivy Cliffs = 9.1° Northeast

The speed of the wind = 25 miles per hour

The direction of the wind = Southeast

The time for the journey = 3 hours

The component of the wind velocity are;

For Southeast direction which is an inclination of 45°

Speed of the wind = -25 × sin(45) + 25 × cos(45)

Without the wind, the velocity of flight will be V = Displacement/time, which gives;

V = 291/3 = 97 miles/hour = 97 mph

Let the required velocity of flying = X, we have;

X×sin(θ) + X×cos (θ) -25× sin(45) + 25 × cos(45) = 97×sin(9.1) + 97×cos(9.1)

X×sin(θ) -25× sin(45) = 97×sin(9.1)

X×sin(θ) = 97×sin(9.1 )+25× sin(45 ) = 33.02

X×sin(θ) = 33.02

X×cos (θ) + 25 × cos(45) = 97×cos(9.1)

X×cos (θ) = 97×cos(9.1)- 25 × cos(45) = 78.1

X×cos (θ) = 78.1

∴X×sin(θ)/(X×cos (θ)) = tan(θ) = 33.02/78.1 = 0.423

tan⁻¹(0.423) = 22.918≈ 22.92°

X×sin(θ) = 33.02

X = 33.02/(sin(θ)) = 33.02/(sin(22.92°)) = 84.79 miles per hour

Therefore, the flight speed should be 84.79 miles per hour at angle of 22.92° Northeast.