AnswersPrecalculusDot Product and Work

Dot Product and Work — Unit test Answers

13 verified answers3 views
4

Given vector u = ⟨1, ⟩ and v = ⟨1, –1⟩, how are the vectors related?

Question illustration
A
The vectors form an acute angle of approximately 75°.
B
The vectors form an acute angle of approximately 81°.
C
The vectors form an obtuse angle of approximately 99°.
D
The vectors form an obtuse angle of approximately 105°.
6

Suppose u · v = 0. Which vectors could represent u and v?

A
u = ⟨3, 4⟩ and v = ⟨4, –3⟩
B
u = ⟨3, 4⟩ and v = ⟨–4, –3⟩
C
u = ⟨–3, 4⟩ and v = ⟨4, –3⟩
D
u = ⟨–3, –4⟩ and v = ⟨–4, –3⟩
7

Consider u = ⟨5, –2⟩ and v = ⟨10, –4⟩. What is the relationship between u and v?

A
The vectors point in the same direction.
B
The vectors form an acute angle.
C
The vectors form an obtuse angle.
D
The vectors point in opposite directions.
9

Given u = ⟨3, 2⟩, v = ⟨1, 5⟩, and the angle between the vectors is 45°, what is u · v?

A
3
B
4
C
13
D
21
11

Consider vectors u = ⟨2, 1⟩ and v = ⟨4, –1⟩ with the angle between them equal to 40°. What are the scalar projections uv and vu?

A
uv = 1.33 and vu = 1.33
B
uv = 1.33 and vu = 3.16
C
uv = 1.71 and vu = 1.33
D
uv = 1.71 and vu = 3.16
12

What is the relationship between vectors u = ⟨1, 0⟩ and v = ⟨0, –3⟩?

A
The vectors form an acute angle of approximately 48°.
B
The vectors form an acute angle of approximately 71°.
C
The vectors are orthogonal because the angle between them is 90°.
D
The vectors form an obtuse angle of approximately 132°.
14

Given u = ⟨1, 3⟩, v = ⟨2, 1⟩, and cos(ϴ) = , where ϴ is the angle between the vectors, what is the scalar projection uv and the dot product u · v?

Question illustration
A
uv = 1.41 and u · v = 4.47
B
uv = 2.24 and u · v = 5.00
C
uv = 2.24 and u · v = 7.07
D
uv = 7.07 and u · v = 15.81

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