Answer to Question #15949 in Mechanics | Relativity for riley groom
use the law of cosines and the law of sines to find the ground speed of an airplane with an airspeed of 120 km/hr @ 20 degrees E of N if the wind is blowing 40 km/hr @ 10 degrees S of E
To find ground speed we, for the beginning will find projections for vector of ground speed.
where V is for velocity,
gr - ground
pl - plane,
w - wind.
x,y - for coordinates, where x- from W to E and y - from S to N.
The same for y, but with cosinuses.