# find the velocity vector and speed of plane relative to the ground

• Jan 9th 2011, 09:20 PM
Taurus3
find the velocity vector and speed of plane relative to the ground
Alright, this is very confusing.

Q. Suppose an airplane is pointing due west and flying with an airspeed of 500mph, and that there is a 200mph wind out of the south west. Find the velocity vector of the plane relative to the ground. What is the speed of the plane relative to the ground?
• Jan 9th 2011, 09:47 PM
snowtea
The velocity relative to ground is the sum of the velocities:
500mph pointing west
200mph pointing north east (from south west)
• Jan 9th 2011, 10:37 PM
Taurus3
so both are positive velocities right?
• Jan 9th 2011, 10:43 PM
Taurus3
so it's just 700 mph?
• Jan 10th 2011, 03:22 AM
snowtea
Quote:

Originally Posted by Taurus3
so it's just 700 mph?

No, the directions matter.
Do you know the rules for vector addition?
You need to use trig.
• Jan 10th 2011, 01:33 PM
mr fantastic
Quote:

Originally Posted by snowtea
The velocity relative to ground is the sum of the velocities:
500mph pointing west
200mph pointing north east (from south west)

@OP: I have highlighted a key word .... (Velocity is very different to speed ....)