Solve Vector Decomposition Homework: F=-11j, v=-i-5j

Thank you for the help!In summary, the force on an object is F = -11j and the vector v = -i-5j. The component of F parallel to v is ProjvF = <-2.115, -10.576> and the component of F perpendicular to v is OrthvF = <2.115, -0.424>. The work done by force F through displacement v is W = 4.664.
  • #1
Turbodog66
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Homework Statement



The force on an object is F = -11j. For the vector v =-i-5j, find:

1. The component of F parallel to v
2. The component of F perpendicular to v
3. The work, W, done by force F through displacement v

Homework Equations



ProjvF = v dot F/ |v|2
OrthvF = F - ProjvF
W = D dot F

The Attempt at a Solution



F = < 0, -11> v = < -1, -5>

1.
ProjvF = -1(0) + -5(-11) / 12 + -52 = 55/26<-1, -5>
ProjvF = <-2.115, -10.576>

2.
OrthvF = < 0, -11> - <-2.115, -10.576> = 0 + 2.115 , -11 +10.576 = <2.115, -0.424>
OrthvF = <2.115, -0.424>

3.
W = <2.115, -0.424> dot < 0, -11> = 2.115(0) + -0.424(-11) = 4.664
W = 4.664I am told that step 1 is correct, and the first value in step 2 is correct. I cannot figure out what I am missing on part 2, which is ultimately messing up step 3. Any help would be appreciated.
 
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  • #2
In 3 you don't do ##\vec v\cdot\vec F## but you use the one that's perpendicular.
In 2 I don't see what's wrong.
 
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  • #3
BvU said:
In 3 you don't do ##\vec v\cdot\vec F## but you use the one that's perpendicular.
In 2 I don't see what's wrong.
Thanks, I see what I did wrong on part 3. Part 2 after redoing it again was expecting -0.42307, I rounded too soon it seems
 

1. What is vector decomposition?

Vector decomposition is the process of breaking down a vector into its component vectors. This is done by finding the horizontal and vertical components of a vector, which can be represented by its x and y values.

2. How do you solve vector decomposition?

To solve vector decomposition, you need to use trigonometric functions such as sine and cosine. First, you need to find the magnitude and direction of the vector, then use these values to find the horizontal and vertical components using trigonometric ratios.

3. What is the formula for vector decomposition?

The formula for vector decomposition is:

Horizontal component (x) = magnitude of vector * cosine of direction angle

Vertical component (y) = magnitude of vector * sine of direction angle

4. How do you find the magnitude and direction of a vector?

The magnitude of a vector can be found using the Pythagorean theorem, where magnitude = √(x² + y²). The direction of a vector can be found using the inverse tangent function, where direction angle = tan⁻¹(y/x).

5. Can you provide an example of solving vector decomposition?

For the given vector F = -11j and v = -i-5j, the magnitude of F is 11 and the direction angle is 270°. The horizontal component of F would be 0 (-11 * cos 270°) and the vertical component would be -11 (-11 * sin 270°). Similarly, the horizontal component of v would be -1 (-1 * cos 180°) and the vertical component would be -5 (-5 * sin 180°). Therefore, the vector decomposition for F would be (0, -11) and for v would be (-1, -5).

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