Math Problem Statement

There are 3 vectors in a 2D coordinate with unit vector π‘₯Μ‚ and 𝑦̂ along x and y axes respectively. The magnitude of π‘Žβƒ— is 5 and it forms an angle of 60π‘œ with the positive x-axis. Vector 𝑏⃗⃗ = 5π‘₯Μ‚ + 8𝑦̂. The coordinates of the starting and ending points of 𝑐⃗ are (4, 5) and (12, 7). Calculate the resultant of π‘Žβƒ— + 𝑏⃗⃗ + 𝑐⃗

Solution

Let's break this problem down step by step, starting with calculating each vector in terms of its components.

Step 1: Vector a\mathbf{a}

  • The magnitude of a\mathbf{a} is given as 5, and it forms an angle of 60∘60^\circ with the positive x-axis.
  • Using trigonometry, we can find the components of a\mathbf{a} along the x^\hat{x} and y^\hat{y} directions.

ax=5β‹…cos⁑(60∘)=5β‹…12=2.5\mathbf{a_x} = 5 \cdot \cos(60^\circ) = 5 \cdot \frac{1}{2} = 2.5 ay=5β‹…sin⁑(60∘)=5β‹…32β‰ˆ4.33\mathbf{a_y} = 5 \cdot \sin(60^\circ) = 5 \cdot \frac{\sqrt{3}}{2} \approx 4.33 So, vector a\mathbf{a} can be expressed as: a=2.5x^+4.33y^\mathbf{a} = 2.5 \hat{x} + 4.33 \hat{y}

Step 2: Vector b\mathbf{b}

  • Vector b\mathbf{b} is directly given as b=5x^+8y^\mathbf{b} = 5 \hat{x} + 8 \hat{y}.

Step 3: Vector c\mathbf{c}

  • The coordinates of the starting point of vector c\mathbf{c} are (4,5)(4, 5) and the ending point is (12,7)(12, 7).
  • To find c\mathbf{c}, we calculate the difference between the ending and starting coordinates.

cx=12βˆ’4=8\mathbf{c_x} = 12 - 4 = 8 cy=7βˆ’5=2\mathbf{c_y} = 7 - 5 = 2 Thus, vector c\mathbf{c} can be expressed as: c=8x^+2y^\mathbf{c} = 8 \hat{x} + 2 \hat{y}

Step 4: Sum of the vectors a+b+c\mathbf{a} + \mathbf{b} + \mathbf{c}

Now, let's sum the three vectors component-wise.

x-component:

Rx=ax+bx+cx=2.5+5+8=15.5\mathbf{R_x} = \mathbf{a_x} + \mathbf{b_x} + \mathbf{c_x} = 2.5 + 5 + 8 = 15.5

y-component:

Ry=ay+by+cy=4.33+8+2=14.33\mathbf{R_y} = \mathbf{a_y} + \mathbf{b_y} + \mathbf{c_y} = 4.33 + 8 + 2 = 14.33

Step 5: Magnitude of the resultant vector

The magnitude RR of the resultant vector can be found using the Pythagorean theorem: R=(Rx)2+(Ry)2=(15.5)2+(14.33)2R = \sqrt{(\mathbf{R_x})^2 + (\mathbf{R_y})^2} = \sqrt{(15.5)^2 + (14.33)^2} Rβ‰ˆ240.25+205.35=445.6β‰ˆ21.11R \approx \sqrt{240.25 + 205.35} = \sqrt{445.6} \approx 21.11

Step 6: Direction of the resultant vector

The direction ΞΈ\theta (with respect to the positive x-axis) can be found using the tangent function: ΞΈ=tanβ‘βˆ’1(RyRx)=tanβ‘βˆ’1(14.3315.5)\theta = \tan^{-1} \left( \frac{\mathbf{R_y}}{\mathbf{R_x}} \right) = \tan^{-1} \left( \frac{14.33}{15.5} \right) ΞΈβ‰ˆtanβ‘βˆ’1(0.924)β‰ˆ42.67∘\theta \approx \tan^{-1} (0.924) \approx 42.67^\circ

Final Result:

The resultant vector R\mathbf{R} has:

  • Magnitude: approximately 21.1121.11
  • Direction: approximately 42.67∘42.67^\circ above the positive x-axis.

Would you like more details or have any questions?

Here are 5 related questions for further exploration:

  1. How would the result change if the angle of vector a\mathbf{a} was different?
  2. Can you verify the magnitude and direction of the resultant vector using graphical methods?
  3. How does the position of vector c\mathbf{c} affect the overall resultant?
  4. What would happen if vector b\mathbf{b} was negative in both components?
  5. How can you decompose the resultant vector into unit vector form?

Tip: Always keep track of the angle direction (above or below the x-axis) when calculating vector components!

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Math Problem Analysis

Mathematical Concepts

Vector Addition
Trigonometry
2D Coordinate Geometry

Formulas

Component form of vectors: a_x = a * cos(ΞΈ), a_y = a * sin(ΞΈ)
Resultant of vectors: R = sqrt(R_x^2 + R_y^2)
Direction of resultant: θ = tan⁻¹(R_y / R_x)

Theorems

Pythagorean Theorem
Trigonometric functions (sin, cos, tan)

Suitable Grade Level

Grades 10-12