- #1
javaistheman
- 8
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I'm currently reviewing for a final tomorrow, I need to score a B on the final to stay in school. I'm beginning to panic as I've reviewed all day and have gotten nowhere.
1. Homework Statement
The tension in the cable AB is 800 lb. Determine the reactions at the fixed support C.
So I'm basically trying to get a fundamental grasp of these problems and just can't seem to do it. I just need to know the logic behind each step. I have a solution key that is lacking the steps, and the steps are what I need.
Firstly, they write out the equation: 800*[(2i-4j-k)/sqrt21]. I'm assuming that these position numbers came from the difference in distance of B from A. But why is it being divided by the square root of 21? And what piece of information does this equation actually give you?
Next they write out rCA = 4i + 5k. I assume here they are getting the distance component of the CA beam.
The next step, they suddenly have all three component of C figured out. How?
Then in the final step, they have the moment figured out for each component of C. Now, I know to get to here from the previous step you'd multiply the magnitudes of the components by the perpendicular distance. Would it be the perpendicular distance from C to A? I assume this because the force is coming out of point A.
If anybody could give me clarity on these things, I'd be grateful. I don't know where else to turn.
1. Homework Statement
The tension in the cable AB is 800 lb. Determine the reactions at the fixed support C.
The Attempt at a Solution
So I'm basically trying to get a fundamental grasp of these problems and just can't seem to do it. I just need to know the logic behind each step. I have a solution key that is lacking the steps, and the steps are what I need.
Firstly, they write out the equation: 800*[(2i-4j-k)/sqrt21]. I'm assuming that these position numbers came from the difference in distance of B from A. But why is it being divided by the square root of 21? And what piece of information does this equation actually give you?
Next they write out rCA = 4i + 5k. I assume here they are getting the distance component of the CA beam.
The next step, they suddenly have all three component of C figured out. How?
Then in the final step, they have the moment figured out for each component of C. Now, I know to get to here from the previous step you'd multiply the magnitudes of the components by the perpendicular distance. Would it be the perpendicular distance from C to A? I assume this because the force is coming out of point A.
If anybody could give me clarity on these things, I'd be grateful. I don't know where else to turn.