An aeroplane leaves point A (40N,78W) and flies due west at 600km/h.if it travels for 3 hours and 20 Minutes.what is the longitude of it's positions.
if the radius of the earth is R, then at latitude 40N, the radius is R'=R cos40°
600 km/hr * 3 1/3 hr = 2000 km
so the new longitude is
78° + 2000/(2πR') * 360° West
so now, look up R, and plug and chug