# Another Moment Question

1. Feb 1, 2007

### suspenc3

I just realized this is in the wrong place..Move it to intro to physics please. Sorry

1. The problem statement, all variables and given/known data
Using Cartesian vector analysis determine the moment of the three forces about the base of the column at A. F1 =400i +300j+120k

2. Relevant equations

The $$x$$ represents "cross"..i dont know the latex for it

$$M_a = r x F$$ (summation)

3. The attempt at a solution

I keep getting the wrong answer and I think it has something to do with the point E. What does this have to do with anything?

What I am doing is summing all the forces crossed with their distances.

$$r_B={12k}N$$
$$r_{F3}={0i-j+8k}N$$

So $$M_A = (r_B x F_1) + (r_B x F_2) + (r_{F3} x F_3)$$

#### Attached Files:

• ###### force_1.jpg
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Last edited: Feb 1, 2007