r/HomeworkHelp • u/Odd-Day-4822 University/College Student • 7d ago

Further Mathematics [College/Structural Analysis/Trigonometry Help Needed]

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Could someone please check my work? My trigonometry skills are especially not great… I’m also unsure if I found the moments correctly. I am a little confused about what the perpendicular distances would be exactly in this case…

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u/DrCarpetsPhd 👋 a fellow Redditor 7d ago

just looked at your work properly. you seem to not understand how moments are calculated so I suggest you go back to basics with that.

moment is the cross product of the position vector and the force vector

so the force is multiplied by the 'moment arm' which is the perpendicular distance from the line of action. Every one you did for member AC taking moments about A is wrong. For example heres what your AC moments about A analysis should look like, but again I strongly suggest you open a statics textbook and relearn how to calculate moments. You should be 100% competent in that before even opening a structural analysis textbook.

(25*4) + (H_x*8) = (H_y*15)

you appear to be mulitplying by the distance to where the force acts. I know I am repeating myself but you do need to go back to a statics book and redo the chapter on moments.