Relative velocity problem. NEED HELP.

  • Thread starter sanghoon
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  • #1
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Homework Statement


A jet airliner moving initially at 300 mph due east enters a region where the wind is blowing at 100 miph in a direction 30° north of east. What is the new velocity of the aircraft relative to the ground?


Homework Equations


I don't know any equations for this question.


The Attempt at a Solution


I thought it might be like using the 300 mph... caculate the hypotenus velocity vector using the angle, and add 100 mph... I don't think it's right.
 
Last edited:

Answers and Replies

  • #2
Astronuc
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This is a vector addition problem. One adds the planes velocity vector to the winds velocity vector. The plane is supported/carried by the wind and the wind is moving, which is much like a boat in a river with a current.

So pick a coordinate system, and the determine the components of each vector.

Pick the direction to East as +x, and the direction to North as +y.
 
  • #3
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Oh wait... so if the plane's velocity vector was A, and the wind's velocity vector was B.
It would be B + A = R?
R being the new velocity vector relative to the ground.
 
Last edited:
  • #4
Astronuc
Staff Emeritus
Science Advisor
19,843
3,327
Oh wait... so if the plane's velocity vector was A, and the wind's velocity vector was B.
It would be B + A = R?
R being the new velocity vector relative to the ground.
Correct!
 
  • #5
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Thank you very much. Much easier when you have another to think with.
 

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