# Homework Help: A Crane problem

1. Dec 7, 2009

### dreistein

1. The problem statement, all variables and given/known data
I'm to design a crane, and therefore I need to find the reactions in the jib and also make the crane stable.
1. I need to find the max. load that the crane is able to lift. Therefore i have to find the reactions where the horisontal and vertical boom is meeting.
2. I need to find out the moment in the bottom of the vertical beam in order to make the crane stable. Now i should have the max weight, and therefore the weight of the stone. And it should be easier to calculate

2. Relevant equations

3. The attempt at a solution
The sum of all the forces needs to be 0. F=0
The angle is 90 degrees, so that is not going to be a problem
The wire from the horisontal beam is only ½ m.
But since i don't know the weight of the stone, I don't know where to begin?

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2. Dec 7, 2009

### dreistein

as i'm using a pulley system i found out that my weight max is going to be 600 kg, but is my crane able to do this? What will the reactions be where they meet each other? And will they be able to lift this?

3. Dec 7, 2009

### dreistein

I assume that the reaction would be: moment = 0, 6000N*3m-R*3m=0
Therefore Reaction where the beams are meeting would be 6000N