# Torque Equilibrium and Elasticity problem

1. Feb 15, 2012

### Elysian

1. The problem statement, all variables and given/known data
A 300 kg nonuniform boom, 6.0 m long, is loosely pinned at the pivot at P. A 1000 kg
block is suspended from the end of the boom at A. The boom forms a 30° angle with
the horizontal, and is supported by a cable, 4.0 m long, between points D and B. Point
B is 4.0 m from P, and point D is 4.0 m above P. The center of mass of the boom is at
point C, which is 2.0 m from P. Find the tension in the cable, and the x- and
y-components of the force of the pivot on the boom.

http://img202.imageshack.us/img202/262/50669209.jpg [Broken]

2. Relevant equations

3. The attempt at a solution

I calculated torques clockwise and counterclockwise and set them equal to each other, which are perpendicular so using the weight I solved for the Force perpindicular

(Fw(rod)*cos(30)*2)+(Fw(block)*cos(30)*6) = Ftcos(30)*4,

this gives me the Force of tension in the rope, from which i use to split into its X and Y components, and then I get the incorrect answer.

any help would be appreciated, thanks in advance

Last edited by a moderator: May 5, 2017
2. Feb 15, 2012

### ehild

Hi Elysian,
You get the force of friction from your equation.
The next question is the x and y components of the force of the pivot. That force is not the same as the tension. Show your work in detail.

ehild