# Bars in Equilibrium Question

1. Nov 1, 2009

### physq

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

The bars are in equilibrium, each l = 3 m
long, and each weighing W = 90 N. The
string pulling down on the two bars is at-
tached a = 0.8 m from the fulcrum on the
lower bar and b = 0.7 m from the left end
of the upper bar. The spring, of constant
k = 28 N/cm is attached at an angle $$\theta$$ = 36 degrees at
the left end of the upper bar.

If the suspended mass is m = 3 kg, by how
much will the spring stretch? Answer in units
of cm.

It is problem 4 in this link (includes picture and answer): http://webphysics.iupui.edu/152/152Sp08/homework/tp19s.pdf [Broken]

2. Relevant equations

Force of a spring(N) = -k(N/m) x(m)

3. The attempt at a solution

I really have no idea where to begin. I'm not trying to just get an answer the answer is inlcuded in the file I would just like a step-by-step explanation of how to get to the answer. Thanks

Last edited by a moderator: May 4, 2017