Moment vector expression to magnitude of moment

AI Thread Summary
The discussion focuses on finding the magnitude and angle of a moment vector given as moment = -2.8i - 1.53j + 2.24k. Participants clarify that the magnitude of a vector can be calculated by squaring each component, summing them, and taking the square root. There is confusion regarding the use of trigonometric functions to determine angles, with one participant noting that the inverse tangent of the vectors does not yield accurate results. The conversation emphasizes the importance of correctly applying vector magnitude formulas. Overall, the thread highlights common challenges in vector calculations and the need for clarity in solving such problems.
kleeds
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Homework Statement


find the magnitude and angle of the moment

moment=-2.8i-1.53j+2.24k

force tension=2.4 kN

Homework Equations


rxf=rfsin(theta)

The Attempt at a Solution


i used the cross product to get i j and k
tried sin and cos of vectors but didnt work.
inverse tan of vectors won't give close to correct angles
 
Last edited:
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Welcome to PF!

As far I as I can tell, the first part of the question is simply asking what the magnitude of the given vector is. You have all three components of the vector.

What is the expression for the magnitude of a vector in terms of its components?
 
I have no idea. The last time i did vectors at least six months ago.
 
nevermind you square them all, add them, then take the square root.
 
kleeds said:
nevermind you square them all, add them, then take the square root.

Yeah.
 

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