Hey, i'm having some difficulty calculating couple moment. i understand that [tex]\sum[/tex]M = [tex]\sum[/tex]Fd. here's an example:(adsbygoogle = window.adsbygoogle || []).push({});

it asks to resolve the couple forces.

the answer is:

(4/5)(60lb) = 48lb

and

(40lb)(cos30)

[tex]\sum[/tex]M = -(48lb)(4ft) + (40lb)(cos30)(8ft)

Now, i don't understand why "-(48lb)(4ft)" is negative. I'm not sure when to use a negative value. Can someone explain this to me?

Cheers

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# Couple forces

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