Representing two couples by a force F

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Homework Help Overview

The problem involves analyzing two couples represented by a force F and a moment M, with a focus on determining their values and the total moment exerted by the couples. The context is within applied mathematics, specifically dealing with torque and forces.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the representation of the couples and the implications of their definitions, questioning how to derive F and M. Some express uncertainty about the relevance of additional dimensions and whether the resultant force could be zero due to the nature of couples.

Discussion Status

The discussion is ongoing, with various interpretations being explored regarding the values of F and M. Some participants have offered insights into the nature of couples and their effects on resultant forces, while others seek clarification on the problem setup.

Contextual Notes

There is a lack of specific information regarding the dimensions of the system, which some participants believe may be irrelevant. The original poster expresses confusion about solving for F, despite having a value for M.

TheRedDevil18
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Homework Statement



Sorry if I posted in the wrong section, this is actually an App Maths question, but anyway

The two shafts are subjected to the
torques (couples) shown.

(a) If you represent the two couples by a force F acting
at the origin O and a couple M, what are F and M?

(b) What is the magnitude of the total moment exerted
by the two couples?

Diagram:

21ec0p3.jpg


Homework Equations





The Attempt at a Solution



I do know what M is, long story but my final answer is 6.05Nm. I just don't get how to solve for F and I am completely stuck, any help ?
 
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∑F=ma

And check your units.
 
Last edited:
I'm subscribing out of curiosity; could you fill in something under 2. and relate to us the long story ? I take it you added up the two pseudovectors ?
 
BvU said:
I'm subscribing out of curiosity; could you fill in something under 2. and relate to us the long story ? I take it you added up the two pseudovectors ?

Firstly I found the components of the moments by using simple trigonometry. I then summed them up and finally to get the magnitude I squared each component added them and took the square root
 
TheRedDevil18 said:

Homework Statement



Sorry if I posted in the wrong section, this is actually an App Maths question, but anyway

The two shafts are subjected to the
torques (couples) shown.

(a) If you represent the two couples by a force F acting
at the origin O and a couple M, what are F and M?

(b) What is the magnitude of the total moment exerted
by the two couples?

Diagram:

21ec0p3.jpg


Homework Equations





The Attempt at a Solution



I do know what M is, long story but my final answer is 6.05Nm. I just don't get how to solve for F and I am completely stuck, any help ?
Do you have the dimensions of the cube ?
 

Attachments

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SammyS said:
Do you have the dimensions of the cube ?
Dimensions of the cube are irrelevant.
 
No, the dimensions are not given. I think the force is zero because the two couples each have two equal and opposite forces(by definition of a couple) that would cancel. Is that correct ?
 
TheRedDevil18 said:
No, the dimensions are not given. I think the force is zero because the two couples each have two equal and opposite forces(by definition of a couple) that would cancel. Is that correct ?

I think you are correct. ... but then I'm the guy who asked about dimensions.
 
I agree the resultant force is zero.
 

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