Equilibrium on a uniform beam

1. Jan 18, 2010

tomsdubs

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

A uniform beam is supported at its centre of gravity. The forces, F, 4N and 6N act to keep the beam in equilibrium. Forces 4N and 6N are acting at 60deg to the horizontal, calculate the force F, if the beam remains in equilibrium.

F is acting upwards on the left of the beam with 4N at 60deg downwards. 6N is on the right acting at 60deg downwards.

2. Relevant equations

Now we know the physics teacher got this wrong and the answer to F will actually be a negative acting downwards from the top.

3. The attempt at a solution

I dont know where to start could someone outline the working for a solution?

2. Jan 18, 2010

Phyisab****

What force are you trying to calculate?

3. Jan 18, 2010

PhanthomJay

As I understand the problem, there is a beam of length L supported at L/2 from one end, at the cg of the beam. Then there is a 6 N force appied at the right end, acting 60 degrees downward from the x axis, and a 4 N force at the left end, acting 60 degrees downward from the x axis, and another force at the left, unknown, labeled F, acting vertically in an unknown up or down direction. If that's the case, sum moments of the vertical components of all forces about the center support = 0, and solve for F, and determine whether it acts up or down.

4. Feb 25, 2010

tomsdubs

Equilibrium on a uniform beam problem

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

Could someone please explain how i would solve this from the basics? I cant find any similar examples in my text books. All i remember is that the teacher made a slight mistake and the result may be negative?

2. Relevant equations

3. The attempt at a solution

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5. Feb 25, 2010

tiny-tim

You asked this before, but you never replied to the help you were given …
You need to use moments.

Show us what you've done, and where you're stuck, and then we'll know how to help.

6. Feb 25, 2010

Staff: Mentor

Moderator's Note: Threads merged.