Relative velocity of plane with vectors

In summary, the problem involves finding the speed and heading of a plane with respect to the ground, given its speed and direction relative to the air and the air's speed and direction relative to the ground. It is solved by using vector addition and trigonometry to find the magnitude and direction of the plane's velocity relative to the ground.
  • #1
Yae Miteo
41
0

Homework Statement



The problem is worded thus:

You are on an airplane traveling 30° south of due west at 130 m/s with respect to the air. The air is moving with a speed 30 m/s with respect to the ground due north.

(a) What is the speed of the plane with respect to the ground?

(b) What is the heading of the plane with respect to the ground? (Let 0° represent due north, 90° represents due east).

Homework Equations



No formulas given

The Attempt at a Solution



I attempted to solve the problem by putting it on a N-E coordinate plane, with two vectors. (North as y, east as x).

For wind:
[tex] \vec{v} = 0\hat{i} + 30\hat{\jmath} [/tex]
For the plane, I do not know how to set up a vector. My plan was to do so, and then find its magnitude so that I can find the plane's speed relative to the ground. 130 m/s is given as the plane's speed relative to the air, but I need to figure out how to relate that to the ground. Any ideas?

For part b, I think I need to know how to do "a" first.
 
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  • #2
Yae Miteo said:

Homework Statement



The problem is worded thus:

You are on an airplane traveling 30° south of due west at 130 m/s with respect to the air. The air is moving with a speed 30 m/s with respect to the ground due north.

(a) What is the speed of the plane with respect to the ground?

(b) What is the heading of the plane with respect to the ground? (Let 0° represent due north, 90° represents due east).

Homework Equations



No formulas given

The Attempt at a Solution



I attempted to solve the problem by putting it on a N-E coordinate plane, with two vectors. (North as y, east as x).

For wind:
[tex] \vec{v} = 0\hat{i} + 30\hat{\jmath} [/tex]
For the plane, I do not know how to set up a vector. My plan was to do so, and then find its magnitude so that I can find the plane's speed relative to the ground. 130 m/s is given as the plane's speed relative to the air, but I need to figure out how to relate that to the ground. Any ideas?

For part b, I think I need to know how to do "a" first.

Have you tried breaking up the given plane vector into components?
 
  • #3
Yae Miteo said:
No formulas given
... in the problem statement - but that does not mean there are no relevant equations.

I attempted to solve the problem by putting it on a N-E coordinate plane, with two vectors. (North as y, east as x).
... that's a decent idea.

For wind:
[tex] \vec{v} = 0\hat{i} + 30\hat{\jmath} [/tex]
Fair enough.

For the plane, I do not know how to set up a vector.
... use trigonometry.

My plan was to do so, and then find its magnitude so that I can find the plane's speed relative to the ground. 130 m/s is given as the plane's speed relative to the air, but I need to figure out how to relate that to the ground. Any ideas?
You could also just use your knowledge of geometry - vectors are arrows pointing in some direction with some length - so sketch them out.
You will need to either add or subtract the vectors to get the result you need.
 

Related to Relative velocity of plane with vectors

What is relative velocity?

Relative velocity is the velocity of an object or observer as measured from the frame of reference of another object or observer.

How is relative velocity calculated?

Relative velocity is calculated by subtracting the velocity of one object from the velocity of another object in the same direction.

What are vectors?

Vectors are quantities that have both magnitude and direction, and are represented by an arrow pointing in the direction of the vector.

How are vectors used to calculate relative velocity?

Vectors are used to represent the velocities of the two objects, and then the vector subtraction is used to find the relative velocity.

Can relative velocity be negative?

Yes, relative velocity can be negative if the two objects are moving in opposite directions or if the vector subtraction results in a negative value.

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