Find the moment about the and axis

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The discussion focuses on calculating the moment about axis AC using the force vector F and the unit vector Uac. The user provided their calculations for the moment, arriving at a result of MomentAC = -1.2. Another participant pointed out a discrepancy in the cross product calculation of Rab and F, suggesting an alternative method that yielded different results. The conversation emphasizes the importance of accurately computing the cross product to achieve the correct moment. Clarifications on the calculations and methods are central to resolving the differences in results.
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1. Homework Statement
http://session.masteringengineering...bs._454_55.jpg
Find the moment about the axis AC. F=<7,12,-6>


2. Homework Equations
MomentAC = Uac dotted with (Rab X F)
Uac is the unit vector from a to c


3. The Attempt at a Solution
Uac=<.8,.6,0>
Rab=<4,3,-2>
F=<7,12,-6>
Rab X F =<6,-10,0>
MomentAC=4.8-6
=-1.2
MomentAC*Uac=<-.96,-.72,0>
 
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The link to the picture is garbage.
 
How did you compute Rab x F? I get a different result.
 
(-6(3)-(-2)12)-(-6(4)-7(-2))+(7(12)-7(3))
(-18+24)-(-24+14)+(48-21)
6,10,27
 
This is different fro what you had before, and this is what I get as well. You just need to do the scalar product now.
 

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