I'm not asking for a solution to this problem. I'm just wondering about its validity. 1. The problem statement, all variables and given/known data The wind velocity v1 is 40mph from east to west while an airplane travels with air speed v2 of 100mph due north. The speed of the airplane relative to the ground is the vector sum v1 + v2. I completely disagree that the speed of the plane relative to the ground is the vector sum v1 + v2. The speed of the object would be changed by a force predicted by the drag equation. It's velocity also is also not constant with time.