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Moment problem

moment problem plz help

1. Homework Statement

a small boat hangs from two davits one of which is shown in the figure. the tension in line ABAD is 369 N. Determine the moent about C of the resultant force Ra exerted on the davit at A

2. Homework Equations



3. The Attempt at a Solution
ok so first i took the 369N and multiplyed it by the unit vector
(2.4i-3.1j-1.2k)/(2.4^+3.1^2+1.2^2)^.5 and got (216,-279,-108)
ok then i took the cross product of (216,-279,-108) and (-2.4,0,0)when i did this i got (0,-259.2,670)but the i component shouldnt be zero please help
 

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Answers and Replies

Tom Mattson
Staff Emeritus
Science Advisor
Gold Member
5,474
20
That distance of 3.1 meters doesn't look like it's parallel to the y-axis, but you're treating it as though it is parallel to it. Is it supposed to be vertical?
 
AlephZero
Science Advisor
Homework Helper
6,953
291
Also, if "line ABAD" means the rope is double between A and B (as in your figure) there are three forces of 369N at point A, not one.
 

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