Math Problem Statement

A vector A has components Ax = −5.50 m and Ay = 8.50 m. Find the magnitude (in m) and the direction (in degrees counterclockwise from the +x-axis) of the vector.

Solution

To find the magnitude and direction of vector A with components Ax=5.50mA_x = -5.50 \, \text{m} and Ay=8.50mA_y = 8.50 \, \text{m}, we can use the following steps:

Magnitude of the vector:

The magnitude AA of vector A is calculated using the Pythagorean theorem: A=Ax2+Ay2A = \sqrt{A_x^2 + A_y^2} Substituting the given values: A=(5.50)2+(8.50)2=30.25+72.25=102.5A = \sqrt{(-5.50)^2 + (8.50)^2} = \sqrt{30.25 + 72.25} = \sqrt{102.5} A10.12mA \approx 10.12 \, \text{m}

Direction of the vector:

The direction θ\theta of vector A (counterclockwise from the positive xx-axis) is found using the tangent function: θ=tan1(AyAx)\theta = \tan^{-1}\left(\frac{A_y}{A_x}\right) Substituting the values: θ=tan1(8.505.50)\theta = \tan^{-1}\left(\frac{8.50}{-5.50}\right) θtan1(1.545)57.5\theta \approx \tan^{-1}(-1.545) \approx -57.5^\circ

Since the vector lies in the second quadrant (because AxA_x is negative and AyA_y is positive), we add 180° to the angle: θfinal=18057.5=122.5\theta_{\text{final}} = 180^\circ - 57.5^\circ = 122.5^\circ

Final Results:

  • Magnitude: 10.12m10.12 \, \text{m}
  • Direction: 122.5122.5^\circ counterclockwise from the positive xx-axis.

Would you like further details or explanations?

Here are some related questions:

  1. How do we calculate the components of a vector given its magnitude and direction?
  2. What are the quadrant rules for angles and their adjustments?
  3. What is the geometric interpretation of the tangent inverse function?
  4. Can you explain the significance of vector direction in physical problems?
  5. How do we add vectors in component form?

Tip: When using inverse trigonometric functions, always check which quadrant the vector is in to adjust the angle properly.

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Math Problem Analysis

Mathematical Concepts

Vector Magnitude
Trigonometry
Quadrant System

Formulas

Magnitude of vector: A = sqrt(Ax^2 + Ay^2)
Direction of vector: θ = tan^(-1)(Ay / Ax)

Theorems

Pythagorean Theorem
Inverse Tangent Function

Suitable Grade Level

Grades 10-12