An aeroplane flies due west for 3 hours from P (lat. 50°N, long. 60°W) to a point Q at an average speed of 600km/h. The aeroplane then flies due south from Q to a point Y 500km away. Calculate, correct to 3 significant figures, (a) the longitude of Q ; (b) the latitude of Y . [Take the radius of the earth = 6400km and ].
Explanation
(a) The distance PQ along the parallel of latitude = speed (km/h) time (h) = 600km/h x 3h = 1800km The longitude of Q = = (b) The distance (Q) along the meridian