Math Problem Statement

Vector A has a magnitude of 10.6 units and points due west. Vector & points due north. (a) What is the magnitude of & if A + & has a

magnitude of 19.6 units? (b) What is the direction of A + & relative to due west? (c) what is the magnitude of & if A - & has a

magnitude of 19.6 units? (d) What is the direction of A - & relative to due west?

(Note: Use the convention that an angle north of west is positive, and an angle south of west is

Solution

Let's solve this problem step by step.

Given:

  • Vector A has a magnitude of 10.6 units and points due west.
  • Vector B points due north.
  • The magnitude of the vector sum A + B is 19.6 units.

Part (a): Magnitude of B if A + B has a magnitude of 19.6 units

We know that A and B are perpendicular to each other because A points west and B points north. Therefore, we can use the Pythagorean theorem to find the magnitude of B:

Magnitude of A+B=A2+B2\text{Magnitude of } A + B = \sqrt{A^2 + B^2}

Substituting the given values:

19.6=(10.6)2+B219.6 = \sqrt{(10.6)^2 + B^2}

Now, solving for B:

19.62=(10.6)2+B219.6^2 = (10.6)^2 + B^2 384.16=112.36+B2384.16 = 112.36 + B^2 B2=384.16112.36B^2 = 384.16 - 112.36 B2=271.8B^2 = 271.8 B=271.816.48 unitsB = \sqrt{271.8} \approx 16.48 \text{ units}

So, the magnitude of B is approximately 16.48 units.

Part (b): Direction of A + B relative to due west

To find the direction of the vector A + B relative to due west, we can use the tangent function:

tan(θ)=BA=16.4810.6\tan(\theta) = \frac{B}{A} = \frac{16.48}{10.6}

Calculating the angle θ:

θ=tan1(16.4810.6)tan1(1.554)57.5 north of west\theta = \tan^{-1}\left(\frac{16.48}{10.6}\right) \approx \tan^{-1}(1.554) \approx 57.5^\circ \text{ north of west}

So, the direction of A + B relative to due west is approximately 57.5° north of west.

Part (c): Magnitude of B if A - B has a magnitude of 19.6 units

For the vector difference A - B, we again use the Pythagorean theorem:

Magnitude of AB=A2+B2\text{Magnitude of } A - B = \sqrt{A^2 + B^2}

Since A - B is also perpendicular (but pointing in different directions), the magnitude is the same as A + B:

19.6=(10.6)2+B219.6 = \sqrt{(10.6)^2 + B^2}

We already solved this in part (a), so the magnitude of B is again 16.48 units.

Part (d): Direction of A - B relative to due west

For the direction of A - B, we calculate:

tan(θ)=BA=16.4810.6\tan(\theta) = \frac{B}{A} = \frac{16.48}{10.6}

But this time, the direction is south of west since B is subtracted:

θ=tan1(16.4810.6)57.5 south of west\theta = \tan^{-1}\left(\frac{16.48}{10.6}\right) \approx 57.5^\circ \text{ south of west}

So, the direction of A - B relative to due west is approximately 57.5° south of west.

Summary of Results:

(a) Magnitude of B = 16.48 units

(b) Direction of A + B = 57.5° north of west

(c) Magnitude of B (for A - B) = 16.48 units

(d) Direction of A - B = 57.5° south of west

Would you like any further details or explanations on these results?

Here are some related questions for further exploration:

  1. How would the results change if vector B pointed east instead of north?
  2. What would be the magnitude and direction of A - 2B?
  3. How do these vector operations apply to real-world navigation?
  4. Can you calculate the resultant vector if B had a different magnitude?
  5. How does changing the angle between A and B affect the results?

Tip: When working with vector problems, always visualize the vectors on a coordinate system to help understand their directions and relationships better.

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Math Problem Analysis

Mathematical Concepts

Vectors
Vector Addition
Vector Subtraction
Pythagorean Theorem

Formulas

Pythagorean theorem: c^2 = a^2 + b^2

Theorems

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Suitable Grade Level

High School