# Statics: Cylinder & Spring system

1. Feb 21, 2008

### spacecataz

1. The problem statement, all variables and given/known data
The linear spring exerts a force at each of its ends that is proportional to the amount of stretch it undergoes. The spring modulus (proportionality constant) is 2 N/cm and its natural (unstretched) length is 1.5 m. Find the normal and friction forces (a) between cylinders A and B and (b) between B and the ground, if the weight of A is 500 N and that of each of B and C is 200 N.

2. Relevant equations
Sum of moments = 0
Sum of forces = 0
fs = kx

3. The attempt at a solution
$$\Sigma$$MAB = N(r/2) - fr(1+$$\sqrt{3}$$/2) + fs(r/2)
$$\Sigma$$MBGround = (mg-N')(r/2) + f'r(1+$$\sqrt{3}$$/2) + fsr

Am I on the right track? I don't really know where to go from here. Please help! Thanks.
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution