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Ch. 7 - Applications of Trigonometry and Vectors
Chapter 8, Problem 7.19

For each pair of vectors u and v with angle θ between them, sketch the resultant.


|u| = 12, |v| = 20, θ = 27°

Verified step by step guidance
1
Step 1: Understand that the resultant vector \( \mathbf{R} \) is the vector sum of \( \mathbf{u} \) and \( \mathbf{v} \).
Step 2: Use the formula for the magnitude of the resultant vector: \( |\mathbf{R}| = \sqrt{|\mathbf{u}|^2 + |\mathbf{v}|^2 + 2|\mathbf{u}||\mathbf{v}|\cos(\theta)} \).
Step 3: Substitute the given values into the formula: \( |\mathbf{u}| = 12 \), \( |\mathbf{v}| = 20 \), and \( \theta = 27^\circ \).
Step 4: Calculate \( \cos(27^\circ) \) using a calculator or trigonometric table.
Step 5: Plug the values into the formula and simplify to find the magnitude of the resultant vector \( |\mathbf{R}| \).

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Vector Addition

Vector addition involves combining two or more vectors to find a resultant vector. This is typically done using the head-to-tail method or by applying the parallelogram law. The magnitude and direction of the resultant vector depend on the magnitudes of the individual vectors and the angle between them.
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Magnitude of a Vector

The magnitude of a vector represents its length and is a measure of how strong or large the vector is. It is denoted by the vertical bars around the vector symbol, such as |u| or |v|. In this question, the magnitudes of vectors u and v are given as 12 and 20, respectively, which are essential for calculating the resultant vector.
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Angle Between Vectors

The angle between two vectors is crucial for determining the direction of the resultant vector. In this case, the angle θ is given as 27°, which affects how the vectors combine. The angle can be used in calculations involving the cosine and sine functions to find the components of the resultant vector.
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