Math Problem Statement

Determine the magnitude and direction (measured counterclockwise from the positive x-axis) of the resultant F_R of the three forces.

Solution

In this problem, you are tasked with determining the magnitude and direction of the resultant force, FRF_R, of the three forces F1F_1, F2F_2, and F3F_3 shown in the diagram. The forces are provided with their magnitudes and the angles relative to the coordinate axes.

Given:

  • F1=30NF_1 = 30 \, \text{N} at an angle of 00^\circ (along the x-axis).
  • F2=5NF_2 = 5 \, \text{N} at an angle of 2020^\circ from the positive x-axis (clockwise direction).
  • F3=60NF_3 = 60 \, \text{N} along the negative y-axis.

We will use vector decomposition to find the components of each force and then sum them to determine the resultant force.

Step-by-Step Solution:

  1. Decompose the Forces into Components:

    • F1F_1 has only an x-component: F1x=F1cos(0)=30NF_{1x} = F_1 \cdot \cos(0^\circ) = 30 \, \text{N} F1y=F1sin(0)=0NF_{1y} = F_1 \cdot \sin(0^\circ) = 0 \, \text{N}

    • F2F_2 has components in both the x and y directions: F2x=F2cos(20)=5cos(20)F_{2x} = F_2 \cdot \cos(20^\circ) = 5 \cdot \cos(20^\circ) F2y=F2sin(20)=5sin(20)F_{2y} = F_2 \cdot \sin(20^\circ) = 5 \cdot \sin(20^\circ)

    • F3F_3 is purely in the negative y-direction: F3x=0NF_{3x} = 0 \, \text{N} F3y=60NF_{3y} = -60 \, \text{N}

  2. Sum the Components:

    • Sum the x-components: FRx=F1x+F2x+F3x=30+5cos(20)+0F_{Rx} = F_{1x} + F_{2x} + F_{3x} = 30 + 5 \cdot \cos(20^\circ) + 0
    • Sum the y-components: FRy=F1y+F2y+F3y=0+5sin(20)60F_{Ry} = F_{1y} + F_{2y} + F_{3y} = 0 + 5 \cdot \sin(20^\circ) - 60
  3. Calculate the Magnitude of the Resultant Force:

    • The magnitude of the resultant force is: FR=FRx2+FRy2F_R = \sqrt{F_{Rx}^2 + F_{Ry}^2}
  4. Calculate the Direction (Angle θ):

    • The angle θ\theta (counterclockwise from the positive x-axis) is given by: θ=tan1(FRyFRx)\theta = \tan^{-1} \left( \frac{F_{Ry}}{F_{Rx}} \right)

Let me calculate these values. math

Given forces

F1 = 30 # N F2 = 5 # N F3 = 60 # N

Calculate components of F2

F2x = F2 * math.cos(math.radians(20)) F2y = F2 * math.sin(math.radians(20))

Components of F1 and F3

F1x = 30 # N (along the x-axis) F1y = 0 # N (along the y-axis)

F3x = 0 # N (along the x-axis) F3y = -60 # N (along the negative y-axis)

Sum of components

FRx = F1x + F2x + F3x FRy = F1y + F2y + F3y

Magnitude of the resultant force

FR_magnitude = math.sqrt(FRx2 + FRy2)

Direction (angle θ in degrees, counterclockwise from the positive x-axis)

theta = math.degrees(math.atan2(FRy, FRx))

FR_magnitude, thetaThe magnitude of the resultant force FRF_R is approximately 67.84 N.

The direction, measured counterclockwise from the positive x-axis, is approximately -59.24°. This negative angle indicates that the resultant force is directed below the x-axis in the fourth quadrant.

If you have any further questions or need additional details, feel free to ask! Here are a few related questions you might find interesting:

  1. How would the direction change if the angle of F3F_3 was different?
  2. What would happen if F2F_2 were applied along the y-axis instead of at 20°?
  3. How can we visualize the vector addition of these forces using a graph?
  4. How does the magnitude of the resultant force change if F1F_1 were increased to 40 N?
  5. What happens if all the forces are acting in the same direction (e.g., 0°)?

Tip: When dealing with forces at different angles, always break them down into components along the x and y axes first—this simplifies the process of calculating the resultant force.

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Math Problem Analysis

Mathematical Concepts

Vector decomposition
Trigonometry
Force addition
Resultant force calculation

Formulas

F_R = sqrt(F_{Rx}^2 + F_{Ry}^2)
theta = tan^(-1)(F_{Ry}/F_{Rx})

Theorems

Pythagorean Theorem
Trigonometric functions (sine, cosine, tangent)

Suitable Grade Level

Grades 9-12