How Do You Determine Moments of a 3D Model?

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SUMMARY

The discussion focuses on calculating moments and torques for a 3D model using the equations Mx = Fz * ya, My = Fx * za, and Mz = -Fx * ya. The participant is following a method demonstrated by their professor, which involves analyzing the torque produced by forces acting on a cube in a counterclockwise (CCW) coordinate system based on the left-hand rule. The expert contributor suggests that each moment equation should include two terms and prompts the participant to consider the cross product of vectors in Cartesian component form to complete their calculations.

PREREQUISITES
  • Understanding of torque and moment calculations
  • Familiarity with vector operations, specifically cross products
  • Knowledge of Cartesian coordinate systems
  • Basic principles of mechanics and forces
NEXT STEPS
  • Study the concept of torque in 3D systems
  • Learn how to compute the cross product of vectors in Cartesian coordinates
  • Explore advanced applications of the left-hand rule in physics
  • Review examples of moment calculations in engineering mechanics
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Students in physics or engineering courses, particularly those focusing on mechanics, as well as educators seeking to clarify concepts related to torque and moments in three-dimensional models.

jeluu9
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Homework Statement


(See pic attachment)

Homework Equations


Moment/Torque = Force * d (Force arm)

The Attempt at a Solution


I have so far
Mx = Fz * ya
My = Fx * za
Mz = -Fx * ya

How I got these answers is by looking at the cube from the component's axis and whether or not it produces a torque. I am following what I observed the professor doing but not sure about why or how one knows how to do this. Please help!

with the coordinate system being CCW is (+) and (+) xyz based on the "left-hand rule"
 

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Hi jeluu9. Welcome to Physics Forums!

There should be two terms in each of these equations, and you already have one of the terms written correctly. Try to figure out what the missing term in each equation is.

Have you learned yet about taking the cross product of two vectors, if the vectors are expressed in cartesian component form?

Chet
 

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