Statics 4.57 - Determine the moment of this force F about an axis extending between A and C.

Question: Determine the moment of this force F about an axis extending between A and C. Express the result as a Cartesian vector.
Problem 4-57 from:
Engineering Mechanics: Statics, 14th edition
Russell C. Hibbeler
Thank you guys for watching.
Please let me know if you have any comments or suggestions and also if you have any other problem you would like to go over with.

[@patientno1797]

amazing explanation, thank you so much :)

[@LearningbyTeaching]

I am glad it was helpful!

[@adriannavarro7974]

Very good explanation, really helped

[@LearningbyTeaching]

I am happy to help! Thanks for watching

[@walat_salih]

Thx sir❤

[@JesusMartinez-zu3xl]

thank you so much!

[@LearningbyTeaching]

Glad to help!

[@georgeray8651]

Hey, why is the Unit vector AB being dot product with the cross product of the Vector AB and force F?

[@LearningbyTeaching]

I am assuming that you meant unit vector AC. If my assumption is right about that then first we do the cross product between AB and force F to find the moment around any point about A, then the component of that moment around the AC direction (That's why we calculated the unit vector AC) can be found by doing the dot product of the previous calculated moment.
This explanation may not be very straight forward, therefore I will recommend to read ONLY page 146 from the book. It should be Chapter 4, under a subsection called Vector Analysis. :)

[@georgeray8651]

@@LearningbyTeaching Thank you so much!

[@sefagokkaya9751]

why dont you take r=cb