Chapter 7: Problem 64
Perform the indicated vector operation. $$ (4 \mathbf{i}-2 \mathbf{j})+(3 \mathbf{i}-5 \mathbf{j}) $$
Short Answer
Expert verified
The resultant vector is \(7 \mathbf{i} - 7 \mathbf{j}\).
Step by step solution
01
Understanding the Problem
Our task is to perform the vector addition of two vectors given in component form: \(4 \mathbf{i} - 2 \mathbf{j}\) and \(3 \mathbf{i} - 5 \mathbf{j}\). This involves adding corresponding components (\(\mathbf{i}\) and \(\mathbf{j}\) components separately).
02
Adding the \(\mathbf{i}\)-Components
Identify the \(\mathbf{i}\)-components of both vectors. The first vector has an \(\mathbf{i}\)-component of 4, and the second vector has an \(\mathbf{i}\)-component of 3. Add them together: \[ 4 + 3 = 7 \]
03
Adding the \(\mathbf{j}\)-Components
Identify the \(\mathbf{j}\)-components of both vectors. The first vector has a \(-2\mathbf{j}\) component, and the second vector has a \(-5\mathbf{j}\) component. Add them together: \[ -2 + (-5) = -7 \]
04
Writing the Resultant Vector
Combine the results of the previous steps to form the resultant vector. The resultant vector is formed by combining the \(\mathbf{i}\)-component and the \(\mathbf{j}\)-component: \[ 7 \mathbf{i} - 7 \mathbf{j} \]
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Component Form
Vector operations, like addition, are easier when vectors are expressed in their **component form**. This means we separate the vector into its horizontal and vertical parts. Instead of a single vector with magnitude and direction, we break it down into how far it goes along the x-axis (horizontal) and along the y-axis (vertical).
- The horizontal part is represented by the
- The vertical part is represented by the j-component.
i-component
The **i-component** of a vector represents the horizontal part of the vector. It tells us how much the vector moves along the x-axis. When you see a vector such as \(4 \mathbf{i}\), it means that the vector moves 4 units to the right.
In the expression \( (4 \mathbf{i} - 2 \mathbf{j}) + (3 \mathbf{i} - 5 \mathbf{j}) \),
In the expression \( (4 \mathbf{i} - 2 \mathbf{j}) + (3 \mathbf{i} - 5 \mathbf{j}) \),
- The first vector contributes a +4 to the i-component.
- The second vector contributes a +3 to the i-component.
j-component
The **j-component** addresses the vertical part of a vector. It represents how much the vector moves along the y-axis. For instance, in \(-2 \mathbf{j}\), the vector moves downwards by 2 units.
Considering our operation \( (4 \mathbf{i} - 2 \mathbf{j}) + (3 \mathbf{i} - 5 \mathbf{j}) \),
Considering our operation \( (4 \mathbf{i} - 2 \mathbf{j}) + (3 \mathbf{i} - 5 \mathbf{j}) \),
- The first vector has a j-component of -2.
- The second vector has a j-component of -5.
Resultant Vector
A **resultant vector** is what you get after performing a vector operation, such as addition. It shows the final direction and magnitude resulting from combining the effects of all vectors involved.
In our exercise, we have added the i-components and j-components separately:
In our exercise, we have added the i-components and j-components separately:
- i-component: \(4 + 3 = 7\)
- j-component: \(-2 + (-5) = -7\)