Statics - 3D Moment about an axis example 1

[@BODYBUILDERS_AGAINST_FEMINISM]

best video on the topic that ive seen so far. thank you for your help, sir.

[@terryheathco5109]

Omg you have helped so much

[@shailkumarjain]

Sir, please advice.. when we replace a force/F with a force couple system, then that couple's moment is free vector, which means we can place that couple anywhere on the system , just that its magnitude should remain the Fd, where d is distance of shift of original force... is that means Fd magnitude need same say 100 N was original force and 1 m is shift of force , so now we can have these combinations as well , 50N-2m or 25N -4m force couples ? ... i was looking for force couple equivalent videos but could not find, please advice. thank you much ..

[@engineeringdeciphered]

I’m not sure what you’re asking. If you replace a force with a force couple system (at a different point), then be sure that the sum of the forces is the same for both cases. And the moment(s) about the point caused by force*distance would be the couple. And your force is now going straight through your point so there’s now Fd anymore. Sorry I don’t teach equivalent force couple systems.

[@shailkumarjain]

@@engineeringdeciphered thank you Sir. Sorry for not drafting question properly. My question is moment of couple in this situation will be free vector as well ? And we can shift moment anywhere else as well ? Thank you much.

[@engineeringdeciphered]

@@shailkumarjain no, these moments that are created by a force are not couples. They are not free vectors. The moment would be different if you calculated it about a different point. Only moments caused by a couple (two forces equal in magnitude and opposite in direction) are free vectors. I think I do have one video on couples.

[@shailkumarjain]

@@engineeringdeciphered ok.. thank you Sir. 🙏

[@reigndrops4090]

When calculating r, how is roc the sam as rod? Are they not different when you turn them into vectors?

[@engineeringdeciphered]

roc and rod are different vectors, and that determinant will have some different numbers inside of it, but the final answer will be the same. As long as the r goes from anywhere on the axis to anywhere on the force, you'll get the same answer. It's pretty cool to try a few different r's and sometimes you can see why they'll give you the same answer.