# 3D Statics

1. Jun 26, 2011

### erainer

Can anyone please help me? I don't know where to start. I've been trying different things for a while now and can't figure it out.

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2. Jun 27, 2011

### Studiot

3. Jun 27, 2011

### erainer

Yes this is homework, and I'm not really sure about how to resolve vectors into components in 3D..

4. Jun 27, 2011

### danR

deleted.

5. Jun 27, 2011

### Studiot

Well if you can do 2D then you can do 3D. It's no inherently more dificult, just a little more complicated because you now have three components, not 2.

What do you know about the Force equilibrium and Moment equilibrium of three forces that meet at a point when they are coplanar (ie 2D)

6. Jun 27, 2011

### erainer

I've only just started my Statics class, so I don't know very much about it.. but I think I figured it out. I just needed to take the components of F1 plus the corresponding components of the other forces equal to 0?

So it would be:

500cos(alpha)=0
alpha=90

500cos(beta)-300=0
beta= 53.1

500cos(gamma)-200=0
gamma= 66.4

7. Jun 28, 2011

### Studiot

Yes if you have realised that two of the forces are along the y and z axes respectively so the resultant of all components along the x axis must be zero.

so 500 cos alpha = zero

and the rest follows as you say.

Hopefully you feel better for having worked this out for yourself with a little prompting.

Please note the forum policy on homework; this thread is a sticky at the top of this forum.