Lever with offset pivot problem

[conneem]

Homework Statement

I have a situation a shown in the diagram below. A lever with a gas compression spring opposing it's turning. I want to find the force acting on the spring, F₁, for a given inital force @ F₀.

[PLAIN]http://img18.imageshack.us/img18/9830/lever01.png [Broken]

Homework Equations

The Attempt at a Solution

I don't think this is a trivial lever problem but I may be wrong?

 

[SammyS]

Welcome to PF.

You're right. It's not trivial.

How do you plan to solve it?

 

[conneem]

I have reduced it to a static problem and am looking at the initial configuration as drawn above, before any movement.

In this situation I believe that F₁ can be worked out by introducing an imaginary lever, as shown below and balancing the moments i.e.

(F₀)(5x) = (F₁)(y)

where y can be found by trigonometry using similar triangles.

However if we revert the problem back to a dynamic one, the length y will change as the system turn and the spring compresses, so for a constant force F₀, F₁ will vary. However I think you could plot this out over a certain turning angle, by just selecting a range of angles and calculating y for that configuration and thus F₁.

I appreciate any comments

[PLAIN]http://img839.imageshack.us/img839/8334/lever02.png [Broken]