Torque and Force question -- Multipe forces acting on an object

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The discussion centers on the analysis of torque and force acting on an object with multiple forces. Participants emphasize the importance of understanding the vector sum of forces, particularly distinguishing between parallel and antiparallel forces. The conversation highlights the need for clarity in problem statements to avoid contradictions in force and torque balance equations. A consistent approach in applying these equations is crucial for accurate results.

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shivam2571
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Homework Statement
The resultant of two unlike parallel forces is10N and acts at a distance of 35cm and 45cm from them. The forces are:
Relevant Equations
F1.d1=F2.d2 (d is perpendicular distance of Axis of rotation to line of action)
F1-F2=10 (since forces are unlike and parallel)
I have attempted and got 2 different solution
1:
1st.jpg

2:
2nd.jpg
 
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Welcome! :cool:
What about the moments?
Is there equilibrium of moments in the system?
 
There seems to be a contradiction in what you posted. The resultant is the vector sum of two forces. If the forces are parallel, the resultant is the sum of the magnitudes. You use the difference of the magnitudes to denote the resultant. That to be correct if the forces are antiparallel, i.e. point in opposite directions. Which is it, parallel or antiparallel?

Better yet, please post the problem statement exactly as was given to you.
 
kuruman said:
There seems to be a contradiction in what you posted. The resultant is the vector sum of two forces. If the forces are parallel, the resultant is the sum of the magnitudes. You use the difference of the magnitudes to denote the resultant. That to be correct if the forces are antiparallel, i.e. point in opposite directions. Which is it, parallel or antiparallel?

Better yet, please post the problem statement exactly as was given to you.
I think the OP is using "unlike" to mean opposite directions.
 
shivam2571 said:
I have attempted and got 2 different solution
1:

2:
In your second solution, your force balance equation assumes the resultant acts in the same direction as as F1, but your torque balance equation assumes it acts in the same direction as F2.
The diagram places the resultant between the two forces. If that were so, taking moments about a point in its line could not produce zero. Had you been consistent in your two equations, I expect you would have got a negative value for one of the forces.
 
haruspex said:
I think the OP is using "unlike" to mean opposite directions.
I took to mean unequal but I can see the interpretation with a hyphen as in unlike-parallel. In any case without a clear statement of the problem as given to OP, one can only guess what it could be. It looks like quite a bit has been lost in translation.
 

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