# Oversimplified Vector Calculus Problem

1. Jan 24, 2010

### XYZeagle

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.

2. Jan 24, 2010

### Staff: Mentor

Presumably the airspeed takes drag into effect. As far as velocity being constant in time, here you are arguing with information given in the problem. The wind and plane speeds are given as constant in this problem. Choosing to not accept the given hypotheses is really not an option.

3. Jan 24, 2010

### XYZeagle

You know the speed of the plane before it encounters wind and the speed of the wind. The drag force caused by the wind will accelerate the plane, thus the changing velocity of the plane over time.

Last edited: Jan 24, 2010