# Homework Help: Find the force F

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1. Jul 6, 2016

### funlord

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

2. Relevant equations
R=Rxi+Ryj

3. The attempt at a solution
I think it has insufficient given but the answer at the back is 234lb.
I assumed that when i put a line through the angle bisector, the line would be perpendicular to the crate

PS: IF the image doesn't load, i put an attachment of the image
Mod note: I have edited your post so that the image now shows.

Last edited by a moderator: Jul 7, 2016
2. Jul 6, 2016

### Grinkle

Edit - I am wrong, sorry.

I think the problem has sufficient information. When you find the equivalent force, you will find an angle and magnitude.

3. Jul 6, 2016

### QuantumQuest

First, create a diagram, if you haven't already done so and use the method you think will lead you to the resultant force. What method would you use?

4. Jul 6, 2016

### Cozma Alex

I say that the sum of the x component has to be equal to the force required, and that of the y componet has to be 0 so here is a system of equations that satisfy this requirements:
(I called X the force of 600lb)

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5. Jul 6, 2016

### Grinkle

Cozma - you need to retract your like. ;-) I was incorrect.

Break the problem into multiple steps - the first step is to combine the forces as drawn to a single force, just a QuantumQuest suggested..

6. Jul 6, 2016

### funlord

It doesn't say that the crate will be pulled horizontally. Therefore we can't assume that y- component is 0.

7. Jul 6, 2016

### funlord

Then what will be next?
There are three unknowns, therefore it requires three equations

8. Jul 6, 2016

### Cozma Alex

No X is 600 lb, I just called it X

9. Jul 6, 2016

### funlord

I tried the best of what I can do, but it doesn't lead to a possible solution

10. Jul 6, 2016

### funlord

ahh ok, I will try to solve it, if it leads that F is 234lb. Then that's the correct solution

11. Jul 6, 2016

### Grinkle

You are getting ahead of yourself. First - pretend the problem statement is -

"Write an equation for a single equivalent force f in terms of F and the angles given. What is the angle of the resultant force f?"

You have enough information in the problem to solve the above. Once you do that, figuring out how to set F to make the magnitude of f any value you want should be clear.

12. Jul 6, 2016

### QuantumQuest

What was that best? Think on your own what you should use to solve the problem and why.

I kindly request to respect PF rules and not give full solutions. There's absolutely no point to do that. No one learns this way.

13. Jul 6, 2016

### Cozma Alex

Sorry, I think I'm wrong :(