Tough systems of equations

1. Feb 13, 2010

Ryuk1990

1. The problem statement, all variables and given/known data

I've got this physics problem where I'm working to find the magnitudes of two force components.

2. Relevant equations

F1sin45 + F2cos30 = 500 lbf

F1sin45 - F2sin30 = 0

3. The attempt at a solution

I've tried so many times by substituting F1 and F2 into both equations but I just can't seem to solve for them. Can someone guide me on how to solve this particular problem step by step because I have to solve a bunch of these.

2. Feb 14, 2010

danago

Can you show us exactly what you are doing to solve the system?

What you could do is re-arrange the second equation to get F1 in terms of F2 and then substitute it into the first equation.

3. Feb 14, 2010

rock.freak667

Both equations 1 and 2 contain F1sin45, you can just subtract equations 1 and 2, and get F2, remember sin30°=1/2 and co30°=√3/2

4. Feb 14, 2010

Jebus_Chris

You can add, divide, subtract equations when dealing with systems.

5. Feb 14, 2010

Ryuk1990

Ok I did what you said, but I end up with this:

F2(√3/2) + F2(1/2) = 500

How do I get F2 alone now?

6. Feb 14, 2010

Aneeshrege

(root 3 +1)F_2/2=500
1000/(root 3+1)=f_2

7. Feb 14, 2010

Ryuk1990

I got 577.35 for F2. Is that right?

8. Feb 14, 2010

Aneeshrege

no. its $$\frac{1000}{\sqrt{3}+1}$$

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