The ground speed of an airplane that has an airspeed of 200 km/h when it is in a 200-km/h crosswind is
A)0 km/h.
B)200 km/h.
C)283 km/h.
D)400 km/h.
E)1600 km/h.

Question

Quizplus · Accepted Answer

The ground speed of the airplane will be the vector sum of its airspeed and the crosswind. Using the Pythagorean theorem, we have:
ground speed = sqrt((airspeed)^2 + (crosswind)^2)
ground speed = sqrt((200 km/h)^2 + (200 km/h)^2)
ground speed = sqrt(2(200 km/h)^2)
ground speed = sqrt(2) * 200 km/h
ground speed = 283 km/h (rounded to the nearest whole number)

The Ground Speed of an Airplane That Has an Airspeed