Quick 2D Motion Question (wind resistance)

[Vroc]

Homework Statement

An airplane is flying 100m/s (N20E) according to the pilot, but is in a wind that is blowing 40 m/s (S10E). What is the plane's real velocity?

Homework Equations

Pythagorean Therom
Cosin and Sin Laws
Component Method

The Attempt at a Solution

Okay, I think I can easily get the answer if I know what this question is asking me. By real velocity, Does it mean the displacement from point 100 m/s (N20E) to 40 m/s (S20E)? Like, I can draw it on a graph and make the triangle. I would then calculate the angle and length of the unknown side. If that's not it, Then how would I go about getting it? Please Help me understand this.

 

[tiny-tim]

Hi Vroc!

An airplane is flying 100m/s (N20E) according to the pilot …
…
Okay, I think I can easily get the answer if I know what this question is asking me.

It means the velocity V_pa of the plane relative to the air is 100 m/s (N20E)

you're given V_ag, the velocity of the air relative to the ground,

and you need to find V_pg, the velocity of the plane relative to the ground.

 

[Vroc]

Hi Vroc!


It means the velocity V_pa of the plane relative to the air is 100 m/s (N20E)

you're given V_ag, the velocity of the air relative to the ground,

and you need to find V_pg, the velocity of the plane relative to the ground.

What? I just need to know what formula to use or how I can use my graph to find the answer.
I'm given the planes Velocity (100m/s n20e) and than the wind (40 m/s s10e)

 

[tiny-tim]

I'm given the planes Velocity (100m/s n20e)

no, that's not the plane's velocity (relative to the ground), it's the plane's velocity relative to the air

now use vector addition

 

[Vroc]

no, that's not the plane's velocity (relative to the ground), it's the plane's velocity relative to the air

now use vector addition

Okay, If I can use vector addiction, than I can do it the way I mentioned earlier by making a triangle and finding the unknown side and angle because they both are ways of finding the same thing. correct?

 

[tiny-tim]

Okay, If I can use vector addiction, than I can do it the way I mentioned earlier by making a triangle and finding the unknown side and angle because they both are ways of finding the same thing. correct?

correct

(and make sure your vector triangle has the arrows the right way round,

so that V_pg = V_pa + V_ag )

 

[Vroc]

correct

(and make sure your vector triangle has the arrows the right way round,

so that V_pg = V_pa + V_ag )

Thank you so much.