1. Sep 25, 2004

### jjiimmyy101

QUESTION: The boom DF of the jib crane and the column DE have a uniform weight of 50 lb/ft. If the hoist and load weight 300 lb, determine the resultant internal loadings in the crane on cross sections through points A, B, and C. (Diagram and answers are attached)

I'm just hoping someone could look at what I did and tell me if I did it correctly.

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• ###### pointB.JPG
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2. Sep 25, 2004

### jjiimmyy101

Here's point C

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• ###### pointC.JPG
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3. Sep 26, 2004

### Jovaro

Looks good to me, but did you take the correct weight for DC in your calculation of point C?

4. Sep 26, 2004

### jjiimmyy101

What I did was find the force acting on the entire beam DF, not just DC.
That's why I got 650 lb (50lb/ft*13ft and it acts @ 6.5ft). Is that the right way to do it? And I was wondering if that force I put right on point D is correct. Thanks for the input.

5. Feb 2, 2010

### MCKilla11

Re: Mechanics

Wouldn't the downward force placed at D be 250 lb?

There is 5 feet of column above cross-section C. So wouldn't you multiply (5 ft)*(50 lb/ft) = 250 lb?