posted by Noah .
An airplane flies due south at 185 km/h relative to the air. There is a wind blowing at 68 km/h to the east relative to the ground. What are the plane's speed and direction relative to the ground?
Vp = 185km/h @270o + 68km/h @ 0o.
X = 185*cos270+68*cos(0)=0+68 = 68km/h.
Y = 185*sin270+68*sin(0)=-185+0=-185km/h
tanAr = Y/X = -185/68 = 2.72059.
Ar = -69.82o = Reference angle.
A = -69.82 + 360 = 290o = Direction.
Vp = X/cosA = 68/cos290=197 m/s=Velocity
@Henry: Where the heck did you get 270??