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Grade 12th passMechanics

The forces 20N,30N,40N,50N and 60N are acting on one of the angular points of a regular hexagon towards the other five angular points taken in order. Find the magnitude and direction of resultant force?

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8 Years agoGrade 12th pass
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ApprovedApproved Tutor Answer1 Year ago

To find the resultant force acting on one of the angular points of a regular hexagon when multiple forces are applied towards the other points, we can use vector addition. Each force can be represented as a vector, and we will break them down into their components based on the angles they make with the horizontal axis. Let's go through the steps to calculate the magnitude and direction of the resultant force.

Understanding the Forces

In a regular hexagon, each internal angle is 120 degrees. When a force is applied towards the next angular point, we can visualize the forces as vectors originating from one vertex and pointing towards the others. The forces given are:

  • F1 = 20N
  • F2 = 30N
  • F3 = 40N
  • F4 = 50N
  • F5 = 60N

Breaking Down the Forces

We will break each force into its x and y components. The angles for the forces, starting from the positive x-axis and moving counterclockwise, are as follows:

  • F1 (20N) at 0°
  • F2 (30N) at 60°
  • F3 (40N) at 120°
  • F4 (50N) at 180°
  • F5 (60N) at 240°

Calculating Components

Using trigonometric functions, we can find the x and y components of each force:

  • F1:
    • Fx1 = 20N * cos(0°) = 20N
    • Fy1 = 20N * sin(0°) = 0N
  • F2:
    • Fx2 = 30N * cos(60°) = 15N
    • Fy2 = 30N * sin(60°) = 25.98N
  • F3:
    • Fx3 = 40N * cos(120°) = -20N
    • Fy3 = 40N * sin(120°) = 34.64N
  • F4:
    • Fx4 = 50N * cos(180°) = -50N
    • Fy4 = 50N * sin(180°) = 0N
  • F5:
    • Fx5 = 60N * cos(240°) = -30N
    • Fy5 = 60N * sin(240°) = -51.96N

Summing the Components

Now, we can sum all the x and y components to find the resultant force components:

  • Total Fx = Fx1 + Fx2 + Fx3 + Fx4 + Fx5
  • Total Fx = 20 + 15 - 20 - 50 - 30 = -65N
  • Total Fy = Fy1 + Fy2 + Fy3 + Fy4 + Fy5
  • Total Fy = 0 + 25.98 + 34.64 + 0 - 51.96 = 8.66N

Finding the Resultant Force

To find the magnitude of the resultant force, we use the Pythagorean theorem:

Resultant Force (R) = √(Total Fx² + Total Fy²)

R = √((-65)² + (8.66)²) = √(4225 + 75.18) = √(4299.18) ≈ 65.5N

Determining the Direction

The direction (angle θ) of the resultant force can be found using the tangent function:

θ = arctan(Total Fy / Total Fx)

θ = arctan(8.66 / -65) ≈ -7.64°

This angle is measured from the negative x-axis, indicating that the resultant force is directed slightly above the negative x-axis. To express this in standard position, we can add 180° to the angle:

θ ≈ 180° - 7.64° = 172.36°.

Final Result

The magnitude of the resultant force is approximately 65.5N, and it acts at an angle of approximately 172.36° from the positive x-axis, indicating a direction towards the left and slightly upward.