An airplane that flies at 100 km/h in a 100 km/h hurricane crosswind has a ground speed of
A)0 km/h.
B)100 km/h.
C)141 km/h.
D)200 km/h.

Question

Quizplus · Accepted Answer

To find the ground speed, we need to use vector addition. The plane's speed relative to the air is 100 km/h, and the wind speed is also 100 km/h. These can be drawn as vectors in opposite directions. Using the Pythagorean theorem, we can find the resultant vector (the ground speed):
ground speed = sqrt((plane speed)^2 + (wind speed)^2)
ground speed = sqrt((100 km/h)^2 + (100 km/h)^2)
ground speed = sqrt(20,000) km/h
ground speed = 141.4 km/h (rounded to one decimal place)
Therefore, the answer is C).

An Airplane That Flies at 100 Km/h in a 100