Hello all. I'm not sure if this is the correct forum because I'm in the UK and I don't know what "Grade K12" is, but the sort of stuff in this forum seems to be the type of work we're doing.(adsbygoogle = window.adsbygoogle || []).push({});

We've just started some work on moments and equilibrium and I'm having difficulty solving the problems. I understand the theory work, such as the principle of moments, requirements for equilibrium and so on, I just need help in understanding why certain things solve the problems. Anyway, all is revealed below :tongue2:

I've had help from the lecturer and so I have the answers but I'm still a little confused......well alot actually

Here are the two questions:

http://img.photobucket.com/albums/v216/rigdon/questions.jpg

And here are my answers:

http://img.photobucket.com/albums/v216/rigdon/question5.jpg

http://img.photobucket.com/albums/v216/rigdon/question6.jpg

So, for question 5, I understand that Moment = Force x Perpendicular Distance from pivot and that 100N x 3m will give the moment of the weight acting down. But I don't understand how writing the equation 100x3 = Rx8 would allow you to solve R when we are taking points about pivot 'A'. I get it mathematically i.e obviously 100x3 = Rx8 can easily find R, but I mean the moments/equilibrium part of it.

Now for question 6. How does 500x0.4 = T Sin12 x 0.47 allow you to find T? Again I don't mean mathematically, I mean how does it logically work out that that equation can find T......

I know my questions are weird and I would be eternally grateful if someone can make me understand these moments/equilibrium problems.

Thanks in advance

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# Homework Help: Equilibrium and Moments

**Physics Forums | Science Articles, Homework Help, Discussion**