1. The problem statement, all variables and given/known data Sorry, I just have a general question. I know how to calculate velocity of anything relative to the ground, but how do you calculate the velocity of something relative to the air (?) if the velocity of the wind is given. Please explain, with a small example if possible. Thank you. ^_^ 2. What I have so far For example lets say a plane was flying at a velocity of 10 m/s north and the wind was blowing 5 m/s east. I know the velocity of the plane relative to the ground would be sqrt(10^2 + 5^2)[N x Degree E], but how does this work if you have to find the velocity relative to the air?