# Homework Help: Moments and equilibrium homework

1. Mar 19, 2004

Hi all, i've been here before out of geneal interest but this is my first post, so i hope it's in the right spot.

I have a problem that I need an answer to, unfortunately due to sickness i wasn't at school when we were taught the theory of moments (called torque by some).

Anyway my question: I have to replace the force shown in the diagram (below or at the URL below) with a single force at the blue dot (x meters away from the 300N force). It said as a hint we should calculate x first.

Ok, I have NO IDEA how to do this. Any help or just a push in the right direction would be much appreciated.

URL of pic: http://www.geocities.com/gambleonlinecasino/question.gif http://www.geocities.com/gambleonlinecasino/question.gif

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2. Mar 20, 2004

### Taurus

can assume that the system is in equilibrium ?
I'm not quite sure if the 60N.m is two or just a single moment.

So to get x, take the total moment of forces around any point, then solve for x which is the length away from blue dot.
Total of moments around blue dot = -60(Nm) + 300x(sin20)(Nm) = 0
x = 0.58

My conventions are +y is up, +x is to the right, +m clock-wise.

3. Mar 21, 2004