- #1
Frankenstein19
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Homework Statement
Find: The angle between the force vector and the line AO, and the magnitude of the projection of the force along the line AO
Homework Equations
cos(theta)=(A*B)/(|A|*|B|)
The Attempt at a Solution
I thought that since I'm given the force F in cartesian form, that I would need to calculate the component of the force F on the line AO and then use the cos(theta)=(A*B)/(|A|*|B|) but that's not at all what my professor did or what I see other people doing.
I first calculated rao and got -1i+2j-2k and its magnitude to be 3m
Then I got the magnitude component of F along AO by finding the unit vector of rao and multiplying that using the dot product with F
Then now that I have the magnitude of FAO and the positio vector rao I thought I could then calculate FAO in cartesian vector form and THEN I thought I had everything I needed to get the angle by using
cos(theta)=(A*B)/(|A|*|B|) but I'm not getting the right answer
Can someone please tell me what I'm doing wrong
*Also I'm sorry about uploading so many attachments, I always have problems adding pictures and I don't know hot to remove the excess attachments*