Math Problem Statement

Assuming the +x -axis is horizontal to the right for the vectors in the following figure, find the following scalar products:

Part 1

Find A ⋅ B if A = 5.50 m and B = 10.0 m.

Incorrect answer. Marks for this submission: 0.000/1.000.

Part 2

Find A ⋅ C if A = 5.50 m and C = 13.1 m.

Incorrect answer. Marks for this submission: 0.000/1.000.

Part 3

Find 2 B ⋅ C if B = 10.0 m and C = 13.1 m.

A = 30 B= 60 C= 37

Solution

To find the scalar (dot) products of vectors, we use the formula:

AB=ABcos(θ)A \cdot B = |A| |B| \cos(\theta)

where A|A| and B|B| are the magnitudes of vectors AA and BB, and θ\theta is the angle between the vectors.

Part 1: Find ABA \cdot B

Given:

  • Magnitude of A=5.50A = 5.50 m
  • Magnitude of B=10.0B = 10.0 m
  • Angle between AA and BB is θ=30\theta = 30^\circ

The scalar product ABA \cdot B is:

AB=ABcos(θ)=5.50×10.0×cos(30)A \cdot B = |A| |B| \cos(\theta) = 5.50 \times 10.0 \times \cos(30^\circ)

cos(30)=32\cos(30^\circ) = \frac{\sqrt{3}}{2}

AB=5.50×10.0×32=55×32A \cdot B = 5.50 \times 10.0 \times \frac{\sqrt{3}}{2} = 55 \times \frac{\sqrt{3}}{2}

Let's calculate this.

Part 2: Find ACA \cdot C

Given:

  • Magnitude of A=5.50A = 5.50 m
  • Magnitude of C=13.1C = 13.1 m
  • Angle between AA and CC is θ=37\theta = 37^\circ

The scalar product ACA \cdot C is:

AC=ACcos(θ)=5.50×13.1×cos(37)A \cdot C = |A| |C| \cos(\theta) = 5.50 \times 13.1 \times \cos(37^\circ)

cos(37)0.7986\cos(37^\circ) \approx 0.7986

AC=5.50×13.1×0.7986A \cdot C = 5.50 \times 13.1 \times 0.7986

Part 3: Find 2BC2B \cdot C

Given:

  • Magnitude of B=10.0B = 10.0 m
  • Magnitude of C=13.1C = 13.1 m
  • Angle between BB and CC is θ=60\theta = 60^\circ

The scalar product 2BC2B \cdot C is:

2BC=2×BCcos(θ)=2×10.0×13.1×cos(60)2B \cdot C = 2 \times |B| |C| \cos(\theta) = 2 \times 10.0 \times 13.1 \times \cos(60^\circ)

cos(60)=12\cos(60^\circ) = \frac{1}{2}

2BC=2×10.0×13.1×12=10.0×13.12B \cdot C = 2 \times 10.0 \times 13.1 \times \frac{1}{2} = 10.0 \times 13.1

2BC=1312B \cdot C = 131

Let's calculate these values.Here are the results for each part:

Part 1: ABA \cdot B

AB=47.63m2A \cdot B = 47.63 \, \text{m}^2

Part 2: ACA \cdot C

AC=57.54m2A \cdot C = 57.54 \, \text{m}^2

Part 3: 2BC2B \cdot C

2BC=131.00m22B \cdot C = 131.00 \, \text{m}^2

These calculations use the dot product formula and the given magnitudes and angles.

Do you need more details or have any questions?

Here are some related questions that you might find helpful:

  1. What is the dot product of two perpendicular vectors?
  2. How do you find the angle between two vectors using the dot product?
  3. How can the scalar product be used in physics to calculate work done by a force?
  4. What is the geometric interpretation of a scalar product?
  5. How does the dot product differ from the cross product in vector mathematics?

Tip: Remember that the dot product can tell you whether two vectors are orthogonal (perpendicular) when the result is zero!

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Math Problem Analysis

Mathematical Concepts

Vector Mathematics
Scalar Product
Trigonometry

Formulas

A ⋅ B = |A| |B| cos(θ)
cos(θ) for specific angles (e.g., 30°, 37°, 60°)

Theorems

Dot Product Theorem

Suitable Grade Level

Grades 10-12