Vector Addition and Subtraction: Analytical Methods Quiz
The question sheet
Reveal any answer as you study-
What tools does the analytical method use instead of a ruler and protractor?
- Graph paper and calculator
- Geometry and trigonometry
- Only estimation
- Only a protractor
Reveal answer
Answer: Geometry and trigonometry
Source evidence
PDF page 167: For the analytical method of vector addition and subtraction, we use some simple geometry and trigonometry, instead of using a ruler and protractor as we did for graphical methods. However, the graphical method will still come in handy to visualize the problem by drawing vectors using the head-to-tail method. The analytical method is more accurate than the graphical method, which is limited by the precision of the drawing. For a refresher on the definitions of the sine, cosine, and tangent of an angle, see Figure 5.17.
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How does the accuracy of the analytical method compare to the graphical method?
- More accurate
- Less accurate
- Exactly equal
- Cannot be compared
Reveal answer
Answer: More accurate
Source evidence
PDF page 167: For the analytical method of vector addition and subtraction, we use some simple geometry and trigonometry, instead of using a ruler and protractor as we did for graphical methods. However, the graphical method will still come in handy to visualize the problem by drawing vectors using the head-to-tail method. The analytical method is more accurate than the graphical method, which is limited by the precision of the drawing. For a refresher on the definitions of the sine, cosine, and tangent of an angle, see Figure 5.17.
PDF page 176: b. The analytical method is more accurate than the graphical method, because the latter involves some extensive
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What limits the precision of the graphical method?
- The size of the angle
- The units used
- The precision of the drawing
- The number of vectors
Reveal answer
Answer: The precision of the drawing
Source evidence
PDF page 167: For the analytical method of vector addition and subtraction, we use some simple geometry and trigonometry, instead of using a ruler and protractor as we did for graphical methods. However, the graphical method will still come in handy to visualize the problem by drawing vectors using the head-to-tail method. The analytical method is more accurate than the graphical method, which is limited by the precision of the drawing. For a refresher on the definitions of the sine, cosine, and tangent of an angle, see Figure 5.17.
PDF page 176: d. The analytical method is more accurate than the graphical method, because the latter is limited by the precision of the
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What is a component of a two-dimensional vector?
- Half the magnitude of the vector
- A piece pointing in x- or y-direction
- A piece with double the magnitude
- A piece pointing opposite the vector
Reveal answer
Answer: A piece pointing in x- or y-direction
Source evidence
PDF page 168: Since, by definition, , we can find the length x if we know h and by using . Similarly, we can find the length of y by using . These trigonometric relationships are useful for adding vectors. When a vector acts in more than one dimension, it is useful to break it down into its x and y components. For a two-dimensional vector, a component is a piece of a vector that points in either the x- or y-direction. Every 2-d vector can be expressed as a sum of its x and y components.
PDF page 176: a. A component is a piece of a vector that points in either the x or y direction.
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Every 2-d vector can be expressed as a sum of what?
- Three perpendicular vectors
- A scalar and a direction
- Its x and y components
- Two equal magnitudes
Reveal answer
Answer: Its x and y components
Source evidence
PDF page 168: Since, by definition, , we can find the length x if we know h and by using . Similarly, we can find the length of y by using . These trigonometric relationships are useful for adding vectors. When a vector acts in more than one dimension, it is useful to break it down into its x and y components. For a two-dimensional vector, a component is a piece of a vector that points in either the x- or y-direction. Every 2-d vector can be expressed as a sum of its x and y components.
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The x- and y-components of a vector form what type of triangle with it?
- Equilateral triangle
- Right triangle
- Obtuse triangle
- Isosceles triangle
Reveal answer
Answer: Right triangle
Source evidence
PDF page 168: These vectors form a right triangle.
PDF page 168: produce it. In this example, and form a right triangle, meaning that the angle between them is 90 degrees. This is a
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What angle lies between the two perpendicular components of a vector?
- 45 degrees
- 90 degrees
- 180 degrees
- 60 degrees
Reveal answer
Answer: 90 degrees
Source evidence
PDF page 168: produce it. In this example, and form a right triangle, meaning that the angle between them is 90 degrees. This is a
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To find magnitude from perpendicular components, which theorem applies?
- Pythagorean theorem
- Law of cosines
- Law of sines
- Distance formula only
Reveal answer
Answer: Pythagorean theorem
Source evidence
PDF page 170: Since this is a right triangle, the Pythagorean theorem (x + y = h ) for finding the hypotenuse applies. In this case, it becomes
PDF page 174: Now we can find the magnitude of the resultant by using the Pythagorean theorem
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The components of -B are what relative to the components of B?
- Half B's components
- Twice B's components
- The negatives of B's components
- The same as B's components
Reveal answer
Answer: The negatives of B's components
Source evidence
PDF page 174: Discussion This example shows vector addition using the analytical method. Vector subtraction using the analytical method is very similar. It is just the addition of a negative vector. That is, . The components of – are the negatives of the are components of . Therefore, the x- and y-components of the resultant
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In the walking example, the resultant A has magnitude of about how many blocks?
- 5 blocks
- 10.3 blocks
- 15 blocks
- 9 blocks
Reveal answer
Answer: 10.3 blocks
Source evidence
PDF page 169: Then A = 10.3 blocks and , so that
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In the city walk example, the walker's eastward displacement was:
- 10.3 blocks
- 9 blocks
- 5 blocks
- 3 blocks
Reveal answer
Answer: 9 blocks
Source evidence
PDF page 169: This magnitude indicates that the walker has traveled 9 blocks to the east—in other words, a 9-block eastward displacement. Similarly,
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When adding two vectors that are not perpendicular, what is done first?
- Multiply their magnitudes
- Draw a single resultant
- Reverse one vector
- Determine components of each vector
Reveal answer
Answer: Determine components of each vector
Source evidence
PDF page 171: Figure 5.23 To add vectors and first determine the horizontal and vertical components of each vector. These are the dotted
PDF page 173: We will solve for these components and then add them in the x-direction and y-direction to find the resultant. Solution
Physics
Physics by OpenStax, based on original Texas Education Agency material, used under CC BY 4.0. Changes made by Stratacademy.
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