Chapter 7: Problem 27
Find the vector, given its magnitude and direction angle. $$|\mathbf{u}|=16, \theta=100^{\circ}$$
Short Answer
Expert verified
The vector is approximately \(\langle -2.79, 15.76 \rangle\).
Step by step solution
01
Understanding the Problem
We need to find the components of a vector given its magnitude, \(|\mathbf{u}|=16\), and its direction angle \(\theta=100^{\circ}\). This involves converting polar coordinates (magnitude and angle) to Cartesian coordinates (vector components).
02
Formula for the Components
The vector \(\mathbf{u}\) can be represented in component form as \(\mathbf{u} = \langle u_x, u_y \rangle\) where \(u_x = |\mathbf{u}| \cos(\theta)\) and \(u_y = |\mathbf{u}| \sin(\theta)\).
03
Calculating the X Component
Using the formula for the x-component: \(u_x = |\mathbf{u}| \cos(\theta) = 16 \cos(100^{\circ})\). Use a calculator to find \(\cos(100^{\circ})\) and multiply by 16.
04
Calculating the Y Component
Using the formula for the y-component: \(u_y = |\mathbf{u}| \sin(\theta) = 16 \sin(100^{\circ})\). Use a calculator to find \(\sin(100^{\circ})\) and multiply by 16.
05
Compute and Combine Components
Find \(u_x ≈ 16 \cos(100^{\circ}) ≈ -2.79\) and \(u_y ≈ 16 \sin(100^{\circ}) ≈ 15.76\). Thus, the vector \(\mathbf{u} ≈ \langle -2.79, 15.76 \rangle\).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Polar Coordinates
Polar coordinates are a way of representing a point or a vector in a plane using two values: the radial distance and the angle from a reference direction. These two values are:
- Magnitude (or radius): This is the length of the vector measured from the origin to the point in question. In this exercise, the magnitude is 16.
- Direction (or angle): This is measured in degrees or radians and specifies the angle from a reference direction, typically the positive x-axis. For this problem, the direction angle is 100°.
Cartesian Coordinates
Cartesian coordinates express a point or vector using two perpendicular axes, usually labeled as x and y. This system is based on a grid defined by these axes, allowing you to precisely position any point with two numeric coordinates:
- X-coordinate (horizontal component): Specifies the distance along the x-axis.
- Y-coordinate (vertical component): Specifies the distance along the y-axis.
- For x-component: \( u_x = |\mathbf{u}| \cos(\theta) \)
- For y-component: \( u_y = |\mathbf{u}| \sin(\theta) \)
Magnitude and Direction
Magnitude and direction are the core characteristics of any vector. Understanding these helps in visualizing how vectors influence each other in space:
- Magnitude: Represents the length or size of the vector. It is a non-negative number, indicating how far it reaches in its designated direction. In our exercise, the vector has a magnitude of 16.
- Direction: Specifies where the vector is pointing relative to a reference direction. In our case, the direction is set by an angle of 100° from the positive x-axis.
- Convert it from polar to Cartesian coordinates to find its components.
- Understand the resultant force or movement when vectors are combined.
- Predict the motion of objects or understand fields in physics.