Math Problem Statement

Given three vectors \(\vec{a}\), \(\vec{b}\), and \(\vec{c}\) with their magnitudes and directions, calculate the following: 1. \(\vec{a} + \vec{b} + \vec{c}\) 2. \(\vec{a} - \vec{b} - \vec{c}\) 3. \(|\vec{a} + \vec{b}|\) 4. \(|\vec{a} + \vec{b} + \vec{c}|\) 5. \(|\vec{a} + \vec{c}|\).

Solution

The image shows three vectors, a\vec{a}, b\vec{b}, and c\vec{c}, along with their magnitudes and angles:

  • a\vec{a}: Magnitude = 2020, at an angle of 4040^\circ from the horizontal.
  • b\vec{b}: Magnitude = 2020, at an angle of 3535^\circ from the horizontal (in the positive x-direction).
  • c\vec{c}: Magnitude = 1010, directed downward (negative y-direction).

The image also contains these questions:

  1. a+b+c=?\vec{a} + \vec{b} + \vec{c} = ?
  2. abc=?\vec{a} - \vec{b} - \vec{c} = ?
  3. a+b=?|\vec{a} + \vec{b}| = ?
  4. a+b+c=?|\vec{a} + \vec{b} + \vec{c}| = ?
  5. a+c=?|\vec{a} + \vec{c}| = ?

Approach:

  1. Decompose each vector into its x and y components: a=(ax,ay),b=(bx,by),c=(cx,cy)\vec{a} = (a_x, a_y), \quad \vec{b} = (b_x, b_y), \quad \vec{c} = (c_x, c_y)
  2. Perform vector addition or subtraction.
  3. Calculate the resultant vector magnitude using: R=Rx2+Ry2|\vec{R}| = \sqrt{R_x^2 + R_y^2}

I will calculate each step. Let's proceed. math

Vector magnitudes and angles (angles are in degrees)

magnitude_a = 20 angle_a = 40 # degrees

magnitude_b = 20 angle_b = 35 # degrees

magnitude_c = 10 angle_c = 270 # downward, equivalent to -90 degrees

Decompose vectors into x and y components

a_x = magnitude_a * math.cos(math.radians(angle_a)) a_y = magnitude_a * math.sin(math.radians(angle_a))

b_x = magnitude_b * math.cos(math.radians(angle_b)) b_y = magnitude_b * math.sin(math.radians(angle_b))

c_x = magnitude_c * math.cos(math.radians(angle_c)) # cos(270°) = 0 c_y = magnitude_c * math.sin(math.radians(angle_c)) # sin(270°) = -1

Perform operations: vector addition and subtraction

1. a + b + c

R1_x = a_x + b_x + c_x R1_y = a_y + b_y + c_y R1_magnitude = math.sqrt(R1_x2 + R1_y2)

2. a - b - c

R2_x = a_x - b_x - c_x R2_y = a_y - b_y - c_y R2_magnitude = math.sqrt(R2_x2 + R2_y2)

3. |a + b|

R3_x = a_x + b_x R3_y = a_y + b_y R3_magnitude = math.sqrt(R3_x2 + R3_y2)

4. |a + b + c|

R4_magnitude = R1_magnitude # Already calculated in R1

5. |a + c|

R5_x = a_x + c_x R5_y = a_y + c_y R5_magnitude = math.sqrt(R5_x2 + R5_y2)

Results

R1_x, R1_y, R1_magnitude, R2_x, R2_y, R2_magnitude, R3_magnitude, R4_magnitude, R5_magnitude### Results:

  1. a+b+c=(31.70,14.33)\vec{a} + \vec{b} + \vec{c} = (31.70, 14.33)
    Magnitude: 34.7934.79

  2. abc=(1.06,11.38)\vec{a} - \vec{b} - \vec{c} = (-1.06, 11.38)
    Magnitude: 11.4311.43

  3. Magnitude of a+b\vec{a} + \vec{b}: 39.9639.96

  4. Magnitude of a+b+c\vec{a} + \vec{b} + \vec{c}: 34.7934.79 (same as in 1)

  5. Magnitude of a+c\vec{a} + \vec{c}: 15.5815.58

Would you like a detailed step-by-step explanation of how each value was calculated?


Follow-up Questions:

  1. How do we calculate the direction of a resultant vector?
  2. Can you derive the angle between two vectors using their components?
  3. What happens if c\vec{c} is reversed? How do results change?
  4. How can we determine if three vectors are linearly dependent?
  5. Can we generalize this process for vectors in 3D space?

Tip:

Always break a vector into components to simplify operations like addition, subtraction, or magnitude calculation.

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Math Problem Analysis

Mathematical Concepts

Vector Addition
Vector Subtraction
Magnitude of Vectors
Component Form of Vectors

Formulas

Vector components: \(x = r \cos(\theta), y = r \sin(\theta)\)
Magnitude of a vector: \(|\vec{R}| = \sqrt{R_x^2 + R_y^2}\)

Theorems

Pythagorean Theorem for magnitude

Suitable Grade Level

Grades 10-12