BIZOMAT MAKEOS · Mechanics

Resultant of Concurrent Forces

What single force is equivalent to these forces acting at one point?

Resolve up to four coplanar forces acting through one point into X and Y components, the resultant and the equilibrant.

Open the calculatorRuns in your browser. No account needed.

How this tool works

Inputs, units and where to find them

InputUnitTypical source
Force 1
MagnitudeNMagnitude of force 1 from your load analysis.
Direction from +X (anticlockwise)°Direction of force 1, anticlockwise from the +X axis.
Force 2
MagnitudeNMagnitude of force 2.
Direction from +X (anticlockwise)°Direction of force 2.
Force 3
MagnitudeNMagnitude of force 3 (0 if not used).
Direction from +X (anticlockwise)°Direction of force 3.
Force 4
MagnitudeNMagnitude of force 4 (0 if not used).
Direction from +X (anticlockwise)°Direction of force 4.

What each input means

Open an input to see what it is, its units, the worked example and the common mistakes, with a small diagram.

Force 1

What this means: Magnitude
Illustration: MagnitudeA block with an arrow pushing on it; the arrow is the force Magnitude.FExample: 1000 NMagnitude
What it is
The size of this force acting through the common point, from your load analysis, without its direction.
Units and format
Enter a number in N: newtons. The form accepts 0 N or more. Required: the tool does not calculate until every input is valid.
Example
The form opens with 1000 N as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
Get it right
Give the magnitude as a positive number and set its direction with the angle; a force of 0 is skipped.
What this means: Direction from +X (anticlockwise)
Illustration: Direction from +X (anticlockwise)Two lines meeting at a point with an arc between them, marking the angle Direction from +X (anticlockwise).θExample: 0°Direction from +X (anticlockwise)
What it is
The direction this force acts in, measured anticlockwise from the positive X axis in the plane of the forces.
Units and format
Enter a number in °: degrees of angle. The form accepts -360° to 360°. Required: the tool does not calculate until every input is valid.
Example
The form opens with 0° as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
Get it right
Use one X axis for all forces. A clockwise direction can be entered as a negative angle.

Force 2

What this means: Magnitude
Illustration: MagnitudeA block with an arrow pushing on it; the arrow is the force Magnitude.FExample: 800 NMagnitude
What it is
The size of this force acting through the common point, from your load analysis, without its direction.
Units and format
Enter a number in N: newtons. The form accepts 0 N or more. Required: the tool does not calculate until every input is valid.
Example
The form opens with 800 N as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
Get it right
Give the magnitude as a positive number and set its direction with the angle; a force of 0 is skipped.
What this means: Direction from +X (anticlockwise)
Illustration: Direction from +X (anticlockwise)Two lines meeting at a point with an arc between them, marking the angle Direction from +X (anticlockwise).θExample: 60°Direction from +X (anticlockwise)
What it is
The direction this force acts in, measured anticlockwise from the positive X axis in the plane of the forces.
Units and format
Enter a number in °: degrees of angle. The form accepts -360° to 360°. Required: the tool does not calculate until every input is valid.
Example
The form opens with 60° as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
Get it right
Use one X axis for all forces. A clockwise direction can be entered as a negative angle.

Force 3

What this means: Magnitude
Illustration: MagnitudeA block with an arrow pushing on it; the arrow is the force Magnitude.FExample: 0 NMagnitude
What it is
The size of this force acting through the common point, from your load analysis, without its direction.
Units and format
Enter a number in N: newtons. The form accepts 0 N or more. Required: the tool does not calculate until every input is valid.
Example
The form opens with 0 N as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
Get it right
Leave it at 0 when there is no third force; its angle is then ignored.
What this means: Direction from +X (anticlockwise)
Illustration: Direction from +X (anticlockwise)Two lines meeting at a point with an arc between them, marking the angle Direction from +X (anticlockwise).θExample: 0°Direction from +X (anticlockwise)
What it is
The direction this force acts in, measured anticlockwise from the positive X axis in the plane of the forces.
Units and format
Enter a number in °: degrees of angle. The form accepts -360° to 360°. Required: the tool does not calculate until every input is valid.
Example
The form opens with 0° as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
Get it right
Ignored when the matching magnitude is 0.

Force 4

What this means: Magnitude
Illustration: MagnitudeA block with an arrow pushing on it; the arrow is the force Magnitude.FExample: 0 NMagnitude
What it is
The size of this force acting through the common point, from your load analysis, without its direction.
Units and format
Enter a number in N: newtons. The form accepts 0 N or more. Required: the tool does not calculate until every input is valid.
Example
The form opens with 0 N as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
Get it right
Leave it at 0 when there is no fourth force; its angle is then ignored.
What this means: Direction from +X (anticlockwise)
Illustration: Direction from +X (anticlockwise)Two lines meeting at a point with an arc between them, marking the angle Direction from +X (anticlockwise).θExample: 0°Direction from +X (anticlockwise)
What it is
The direction this force acts in, measured anticlockwise from the positive X axis in the plane of the forces.
Units and format
Enter a number in °: degrees of angle. The form accepts -360° to 360°. Required: the tool does not calculate until every input is valid.
Example
The form opens with 0° as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
Get it right
Ignored when the matching magnitude is 0.

Method and formulas

  1. Rx = Σ F cos θ; Ry = Σ F sin θ.
  2. R = √(Rx² + Ry²); direction = atan2(Ry, Rx). The equilibrant has the same size, opposite direction.
  3. Example: 1000 N at 0° and 800 N at 60° give a resultant of 1,562 N at 26.33°.

Limitations

  • All forces must act through the same point in one plane; moments from offset forces are not included.
  • Example values are illustrations. Replace them with values for your actual task.

Typical uses

  • Combine cable, sling or bracket loads
  • Find the reaction a support must provide
  • Check a free-body diagram quickly

Who it is for

  • Design engineers
  • Maintenance engineers
  • Technicians

What you get

  • X and Y components
  • Resultant magnitude and direction
  • Equilibrant

Interpreting the result

  • Design the support or anchor for the equilibrant, with your code’s load factors.

References

  • Machinery’s Handbook, 29th edition (Industrial Press, 2012), printed pp. 153–163. Topic reference; no source tables or recommended settings are reproduced.

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Open the Resultant of Concurrent Forces calculator