The ground speed of an airplane that has an airspeed of 100 km/h when it is in a 100-km/h crosswind is
A)0 km/h.
B)100 km/h.
C)141 km/h.
D)150 km/h.
E)200 km/h.

Question

Quizplus · Accepted Answer

The ground speed is found by calculating the resultant vector of the airplane's airspeed and the crosswind speed. Using the Pythagorean theorem for a right-angled triangle (since the crosswind is perpendicular to the airspeed), the ground speed is √(100^2 + 100^2) km/h = √(20000) km/h = 141 km/h.

The Ground Speed of an Airplane That Has an Airspeed