Can somebody shows me how to calculate for part c. the answer key is 1.365h.

Question

A jetliner travels with a constant speed of 573.7 km/h relative to the air to a city 780.1 km due south.
(a) What is the time interval required to complete the trip if the jetliner is experiencing a headwind of 52.2 km/h toward the north?

h


(b) What is the time interval required to complete the trip if the jetliner now experiences a tailwind of the same speed?
h


(c) What is the time interval required to complete the trip if the jetliner now experiences a crosswind of the same speed relative to the ground towards the west? (Enter your answer to at least three decimal places.)

h

Answer 1

south speed = 573.7 cos A
west speed = 52.2 - 573.7 sin A = 0 if the resultant heads south
sin A = 52.2/573.7
A = 5.227 degrees
cos A = .9958
so
south speed = 573.7*.9958 = 571.3
780.1/571.3 = 1365 sure enough