Determine the resultant couple moment

AI Thread Summary
To determine the resultant couple moment on a beam with two acting couples, the calculation involves using the formula M=Fd, where forces are multiplied by their respective distances. The confusion arises regarding the sign convention for moments, specifically when to use positive or negative values. In this case, clockwise moments are considered positive, while counterclockwise moments are negative. The discussion highlights a lack of clarity in the textbook regarding the right-hand rule, which is essential for understanding the sign convention. Proper application of these principles will lead to the correct determination of the resultant couple moment.
joker2014
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Homework Statement



4-70 Two couples act on the beam. If F=125 lb. determine the resultant couple moment.
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Homework Equations



M=Fd

The Attempt at a Solution


I know CW is + and CCW is - ...and that is determined in the final answer,
I know the solution is taking Forces times the distance, the solution is M=(200*1.5)+(125cos30*1.25)

question is why are they both positive? when do we consider taking negative instead positive? I've seen other solutions for other questions, where they take negative ... I am confused when to take negative or position... so why not -200 or -125 [/B]
 
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Are you sure your textbook doesn't explain this? Like mentioning the right hand rule?
 
it didnt, otherwise i wouldn't ask here... you could have did me favor and explained rather than asking me a non sense question.. thank you anyways.
 
joker2014 said:
it didnt, otherwise i wouldn't ask here... you could have did me favor and explained rather than asking me a non sense question.. thank you anyways.
I dropped a rather big hint.

https://en.wikipedia.org/wiki/Right-hand_rule
 

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