Question

a plane leaves an airport P 10 degrees south,60 degrees east and flies due north at 800km/hr .(a)find its position after 24hrs. (b)the plane turns and flies at the same speed due west to reach Q longitude 12 degrees west.find the distance it has travelled due in west nautical miles.

Answer 1

If the radius of the earth is R at the equator, the radius of the circle of latitude in part (b) is Rcosθ, where θ is the latitude it has reached in part (a).

So, each ° of longitude is (2πRcosθ)/360 km