# Center of forces?

1. Jul 11, 2004

### dedaNoe

How do I find the center of forces?
For instance if given as 3d vectors:
F1, F2 (any forces) and R1, R2 (any positions where they act)
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Where will be the center (R=?) and how much force it'll cary (F=?)?

I'm stacked on this one!
Stack overflow sort of stacked!

2. Jul 11, 2004

### arildno

The concept of the center of forces (C.F). is not particularly useful.
In general, C.F. is defined as the point such that the moment of the sum of forces (acting at C.F) about some other point is equal to the sum of the individual moments of forces (acting from their individual points), computed with respect to the other point.

However, if the sum of forces is zero, the sum of individual moments may well be non-zero, and hence, no point can act as C.F.

3. Jul 12, 2004

### dedaNoe

I think that's how it works for masses. It'll then come down to:
R:=Sum(M_i * R_i) / Sum(M_i)
italic is vector; regular is scalar;
The difference is that mass is scalar while force is vector.
I still need C.F.

4. Jul 13, 2004

### dedaNoe

5. Jul 14, 2004

### dedaNoe

What do you think?