Chapter 3: Problem 2
What is the numerical value of the vector \(3 \hat{\mathbf{i}}+4 \hat{\mathbf{j}}+4 \hat{\mathbf{k}}\) ? (a) \(3 \sqrt{2}\) (b) \(5 \sqrt{2}\) (c) \(7 \sqrt{2}\) (d) \(9 \sqrt{2}\)
Short Answer
Expert verified
The numerical value is \(\sqrt{41}\), not provided in the options.
Step by step solution
01
Understand the Problem
We need to find the numerical value (magnitude) of the vector given by \(3 \hat{\mathbf{i}} + 4 \hat{\mathbf{j}} + 4 \hat{\mathbf{k}}\). This involves finding the magnitude of a three-dimensional vector.
02
Use the Magnitude Formula
The formula to find the magnitude of a vector \(\mathbf{v} = a \hat{\mathbf{i}} + b \hat{\mathbf{j}} + c \hat{\mathbf{k}}\) is \(|\mathbf{v}| = \sqrt{a^2 + b^2 + c^2}\). We will use this formula to find the magnitude of the vector \(3 \hat{\mathbf{i}} + 4 \hat{\mathbf{j}} + 4 \hat{\mathbf{k}}\).
03
Substitute Values Into Formula
Substitute \(a = 3\), \(b = 4\), and \(c = 4\) into the magnitude formula: \[|\mathbf{v}| = \sqrt{3^2 + 4^2 + 4^2}\]
04
Calculate Squared Values
Calculate each component squared: \(3^2 = 9\), \(4^2 = 16\), and \(4^2 = 16\).
05
Sum the Squared Values
Add the squared values found in Step 4: \[9 + 16 + 16 = 41\]
06
Find the Square Root
Find the square root of the sum obtained in Step 5: \[|\mathbf{v}| = \sqrt{41}\]
07
Compare and Select the Correct Answer
Compare \(\sqrt{41}\) to the choices given. Since there's no option \(\sqrt{41}\), we need to check if \(\sqrt{41}\) matches any provided choices when simplified further, but since there's no straightforward match, \(9\sqrt{2}\) is incorrect based on simple estimation. The provided options don't fit \(\sqrt{41}\). Hence, either re-evaluate the interpretation or check for color options after recomputing.
Unlock Step-by-Step Solutions & Ace Your Exams!
-
Full Textbook Solutions
Get detailed explanations and key concepts
-
Unlimited Al creation
Al flashcards, explanations, exams and more...
-
Ads-free access
To over 500 millions flashcards
-
Money-back guarantee
We refund you if you fail your exam.
Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!
Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Three-Dimensional Vector
A three-dimensional vector is one that exists in a space defined by three axes: the x-axis, y-axis, and z-axis. It is often used to represent quantities that have both magnitude and direction in this three-dimensional space, like force or velocity.
For instance, the vector given in the original problem is \(3 \hat{\mathbf{i}} + 4 \hat{\mathbf{j}} + 4 \hat{\mathbf{k}}\). Here, the components 3, 4, and 4 represent the vector's influence along the x, y, and z axes, respectively. Each component can either be positive or negative, indicating the direction along each axis.
For instance, the vector given in the original problem is \(3 \hat{\mathbf{i}} + 4 \hat{\mathbf{j}} + 4 \hat{\mathbf{k}}\). Here, the components 3, 4, and 4 represent the vector's influence along the x, y, and z axes, respectively. Each component can either be positive or negative, indicating the direction along each axis.
- \(\hat{\mathbf{i}}\), \(\hat{\mathbf{j}}\), and \(\hat{\mathbf{k}}\) are unit vectors in the direction of the x, y, and z axes.
- The three-dimensional nature means the vector is a point on or in a spatial plane.
Magnitude Formula
The magnitude formula is used to determine the size or length of a vector without considering its direction. It is particularly useful when you need to understand how much of a quantity is present.
For a vector \(\mathbf{v} = a \hat{\mathbf{i}} + b \hat{\mathbf{j}} + c \hat{\mathbf{k}}\), its magnitude \(|\mathbf{v}|\) is found using the magnitude formula:
\[|\mathbf{v}| = \sqrt{a^2 + b^2 + c^2}\]
For a vector \(\mathbf{v} = a \hat{\mathbf{i}} + b \hat{\mathbf{j}} + c \hat{\mathbf{k}}\), its magnitude \(|\mathbf{v}|\) is found using the magnitude formula:
\[|\mathbf{v}| = \sqrt{a^2 + b^2 + c^2}\]
- This formula is derived from the Pythagorean theorem, which applies in three-dimensional spaces too.
- It adds the squares of each vector component, reflecting the contribution of each dimension.
Vector Components
Vector components are the individual projections of a vector along the axes of a coordinate system. This decomposition of a vector into its components is a crucial skill in physics and mathematics.
The vector \(3 \hat{\mathbf{i}} + 4 \hat{\mathbf{j}} + 4 \hat{\mathbf{k}}\) has three main components:
The vector \(3 \hat{\mathbf{i}} + 4 \hat{\mathbf{j}} + 4 \hat{\mathbf{k}}\) has three main components:
- The \(3 \hat{\mathbf{i}}\) component, which indicates a projection of length 3 along the x-axis.
- The \(4 \hat{\mathbf{j}}\) component along the y-axis.
- The \(4 \hat{\mathbf{k}}\) component along the z-axis.
Euclidean Norm
The Euclidean norm, also referred to as the L2 norm or simply the 'norm', is a commonly used measure of vector magnitude. It shows the distance of a vector from the origin to its endpoint in multi-dimensional spaces.
This measurement is essentially the same as the magnitude for a three-dimensional vector and is calculated with the formula:
\[ |\mathbf{v}| = \sqrt{a^2 + b^2 + c^2} \]
This measurement is essentially the same as the magnitude for a three-dimensional vector and is calculated with the formula:
\[ |\mathbf{v}| = \sqrt{a^2 + b^2 + c^2} \]
- It acts as the "straight-line" distance between two points, one being the origin.
- It is intuitive, as it mirrors real-world concepts of distance.