Velocity of Plane Relative to Ground: Answer & Explanation

[wolves5]

A plane is headed eastward at a speed of 210 km/hr. The wind is blowing southward at 85.0 km/hr. The velocity of the plane relative to the ground is?
a. 192 km/hr at an angle of 22 degrees south of east
b. 192 km/hr at an angle of 22 degrees east of south
c. 227 km/hr at an angle of 68 degrees south of east
d. 227 km/hr at an angle of 68 degrees east of south

For the velocity, I did square root (210^2 + 85.0^2) and I got 227 km/hr. However, when finding the angle, I did tan-1(85/210) and got 22 degrees. I don't know which one would be the correct answer then.

 

[Mandeep Deka]

First tell me,

Which direction does tan^-1(85/225) signify-
east of south or south of east?

The answer to your question lies in this particular answer!

 

[farid yunos]

Hi,

Agree with you.. please justify the direction..