The compass in a light aircraft shows that it is flying due north. The air speed indicator gives a reading of 150km/h. If there is a 50km/h wind blowing from west to east, what is the ground speed of the aircraft?
The plane is moving 150km/h forward, it is also moving 50km/h right. If you draw out the vectors, as shown in the diagram below, then you'll see we want to calculate the hypotenuse of the triangle.Originally Posted by bobby77
use pythagorean theorum...
It depends on your coordinate system. You draw any three mutually perpendicular lines, and your coordinate system is ready(anyone of the three could be x,y and z). But for international convention, a coordinate system is universally accepted(right handed coordinate system).Originally Posted by Quick
Draw a horizontal line and a line perpendicular to it(it will be obviously vertical).Label horizontal as x , vertical as y. Then z will be upwards out of the plane of the paper.
In the question
velocity of plane (without air)=0i+150j+0k
velocity of air=50i+0j+0k
(Actually there is a method which could tell you that the cordinate system used by you is acc. to international convention or not(based on cross product of vectors))