Repeated posting: Add these vectors or subtract them? corrected a typo in the problem

Question

 

A jet plane intended to be on a velocity and course of 870 knots, 44 degrees south of west encounters wind. The flight tower shows that their actual velocity and path is 840 knots, 49 degrees south of west. What was the velocity and direction of the wind?

 

I would appreciate multiple answers on this one because I think the teacher worked this problem totally wrong. thanks (:

Answer 1

John - The actual velocity is the combination of the plane velocity and the wind velocity, so to arrive at the wind velocity you must subtract the plane velocity from actual.

 

You can break the problem down into x and y components:

 

y = 840 sin(180+49) - 870 sin(180+44)

 

x = 840 cos(180+49) - 870 sin(180+44)

 

wind velocity = (x^2 + y^2)^(1/2)

 

wind direction = arctan(y / x)