The air speed indicator of a plane that took off from Detroit reads 373 km/h and the compass indicates that it is heading due east to Boston. A steady wind is blowing due north at 42.3 km/h.

Question

Calculate the speed of the plane with reference to the ground.

If the pilot wishes to fly directly to Boston (due east) what must the compass read? (0 = North, 90 = East, ...)

Answer 1

X = east = 373km/h.

a. Y = north = 42.3km/h.

tanA = Y/X = 42.3 / 373 = 0.1134.
A = 6.47deg.

V = X / cosA = 373 / cos6.47 = 375.4km/h.

b. -6.47deg = 6.47deg South of East.
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