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Resultant and moment

  • Thread starter LMW - Dk
  • Start date
  • #1
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Homework Statement



I have to determine the resultant R and the moment about O.

Homework Equations



see the image.

The Attempt at a Solution



See the image.
 

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Answers and Replies

  • #2
tiny-tim
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Hi LMW - Dk! Welcome to PF! :wink:

Show us what you've tried and where you're stuck, and then we'll know how to help! :smile:
 
  • #3
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See the pictures. I have found the moment and the resultant. However I think it's the wrong method ^^
 
  • #4
tiny-tim
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sorry, i didn't notice your third picture :redface:

your Fz36 should be minus 36, shouldn't it? :smile:

(btw, i think most people find it easier to use cos and sin, of angles < 90°, and then use common-sense to decide whether its + or -)

i don't understand what you did to find the moment :confused:
can you please type it out in the post?​
 
  • #5
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Well can't you tell me how you would do this problem? how would you find the resultant and the moment?
 
  • #6
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If you click on the second picture then you can see that i have drawn a direction vector. Then i have found the cfross product of the direction vector and the resultant force.
 
  • #7
tiny-tim
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If you click on the second picture then you can see that i have drawn a direction vector. Then i have found the cfross product of the direction vector and the resultant force.
ah, now i understand …

no, you've crossed the resultant with the position vector for only one of the vectors: you need to cross each vector with its own position vector, and then add (ie, there's no short-cut)

(and did the minus 36 help?)​
 

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