# What is the magnitude of force vector?

1. Sep 8, 2013

### ozzolins

1. Determine the magnitude of F2

2. How can I find this one force if I know resultant force and other force? Never done this before, that's why I've no idea.

3. Sorry, I have none.

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Last edited: Sep 8, 2013
2. Sep 8, 2013

### Crake

$F_r = F_1 + F_2$

The resultant force is the sum of all forces.

3. Sep 8, 2013

### ozzolins

I know that, but it's a bit more complicated due to the fact that for these forces I need to find x and y components first.

4. Sep 8, 2013

### SteamKing

Staff Emeritus
Well, what's stopping you from finding the components?

5. Sep 8, 2013

### ozzolins

Unknown F2 value.

I came down to:

199.9 = √(0.6x+86.6)2 + (0.8x + 50)2

Though, I can't (don't know how) solve this equations.

NB! I made a mistake and resultant force is 199.9 N.

6. Sep 8, 2013

### SteamKing

Staff Emeritus
Fr = 58.264 N
I don't know where you got 199.9 N

And you could stand an algebra refresher.

7. Sep 8, 2013

### ozzolins

Why do you think it's 58.264N? I made a mistake writing it down in the first post.

This is only part of exercise.

There was resultant moment given of 115 N*m, and distance between Fr and point O (where this moment happens) was 0.575 meters. So I divided 115 by 0.575m and I got resultant force of 199.9N.

Now I need to find F2.

Anyone can help with that, please?

8. Sep 8, 2013

### SteamKing

Staff Emeritus
I'm sorry. The OP had a diagram asking to determine the magnitude of F2. If you want to post the correct problem you are working on, please do so.

9. Sep 8, 2013

### ozzolins

Now the diagram is correct. Still can't figure out magnitude of F2.

10. Sep 9, 2013

### Crake

It seems to me that you're not even trying. Show us what you've done to find $F_2$, show us your work.

Last edited: Sep 9, 2013
11. Sep 9, 2013

### Staff: Mentor

If you call f2 the magnitude of F2, what are its components in the x and y directions (in terms of f2)?

Chet

12. Sep 9, 2013

### D H

Staff Emeritus
Is this your diagram, or is from some book / web site? What's with that 3-4-5 triangle?