PING OUT "Let Vector V = 36 i + 24 j - 57 k"

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In summary, the problem is asking for the angles that a given vector, V = 36i + 24j - 57k, makes with the x, y, and z axes. The i, j, and k symbols represent unit vectors along the x, y, and z axes, respectively. To find the angles, one can use the dot product of the vector and each unit vector, and then use the formula for finding the angle between two vectors. Alternatively, the angle between V and the x-axis can be found by finding the angle between V and the i-vector, which is parallel to the x-axis.
  • #1
physicsss
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how to do this problem:
Let vector V = 36 i + 24 j - 57 k. What angles does this vector make with the x, y, and z axes?

TY
 
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  • #2
What do you think ? Any ideas ?
 
  • #3
Do you know what the dot product (scalar product) is?
 
  • #4
Yea, I know what they are...but aren't they for when you have 2 vectors?
 
  • #5
What makes you think you haven't two vectors at your disposal?
 
  • #6
Can you expand on it more? The problem only gave me one.
 
  • #7
Well, does there exist, for example, a vector which is parallell to the x-axis, so that you could use this in calculating angle between the given vector and the x-axis?
 
  • #8
Could you show me an example? (maybe find the angle a 3-d vector (doesnt have to be mine) makes with the x-axis?)
 
  • #9
What's "i" in your equation?
What does this symbol stand for?
 
  • #10
i is the x-component, j is the y-com, and k is the z-com.
 
  • #11
physicsss said:
Could you show me an example? (maybe find the angle a 3-d vector (doesnt have to be mine) makes with the x-axis?)

how about the X axis?
 
  • #12
physicsss said:
i is the x-component, j is the y-com, and k is the z-com.
Your vector is:
[tex]\vec{V}=36\vec{i}+24\vec{j}-57\vec{k}[/tex]
[tex]\vec{i}[/tex] is a unit vector PARALLELL to the x-axis, the number multiplied with it is the vector's component along the x-axis (that is, the vector's x-component).
Another way of saying this, is that:
[tex]\vec{V}\cdot\vec{i}=36[/tex]
Are you now able to calculate the angle?
 
  • #13
I just began learning dot products, and I have never done such an operation like this...
 
  • #14
physicssss,
i denotes a unit "vector" along x-axis
j denotes a unit "vector" along y-axis
k denotes a unit "vector" along z-axis

if u find angle of x with i , then with j and then with k ...
what will u have eventually?

-- AI
 
  • #15
what is x in this case? I'm really confused...
 
  • #16
physicsssssss, TenaliRaman blundered, his sentence should read:
"if u find angle of V with i , then with j and then with k ...
what will u have eventually?"
Does this clear up?
 
  • #17
not really...is there a formula for finding the angles a vector makes with the axes??
 
  • #18
But the i-vector lies along the x-axis!
So the angle between the vector V and the x-axis must be the same as the angle between i-vector and V
 

1. What does the vector V = 36i + 24j - 57k represent?

The vector V represents a displacement in three-dimensional space, with a magnitude of 36 units in the x-direction, 24 units in the y-direction, and 57 units in the z-direction.

2. How do you calculate the magnitude of vector V?

The magnitude of vector V can be calculated using the Pythagorean theorem, where the magnitude is equal to the square root of the sum of the squares of the individual components. In this case, the magnitude of vector V is approximately 69.78 units.

3. What is the direction of vector V?

The direction of vector V can be determined by finding the angles between the vector and each of the coordinate axes. In this case, the direction of vector V is approximately 35.54 degrees from the positive x-axis, 35.54 degrees from the positive y-axis, and 124.46 degrees from the positive z-axis.

4. How can vector V be represented in unit vector notation?

Vector V can be represented in unit vector notation as V = 36i + 24j - 57k = 69.78(cos 35.54° i + cos 35.54° j + cos 124.46° k).

5. Can vector V be used to represent a physical quantity?

Yes, vector V can represent a physical quantity such as displacement, velocity, or force, depending on the context in which it is being used. For example, if vector V represents a displacement, its units would be in meters (m).

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