I am having trouble using the right hand rule properly and often find myself putting my hand in awkward orientations. I know you point your hand in the direction of $r$ and then point your fingers in the direction of $F$ but that doesn’t really help me. Can anyone explain how to use it correctly and without awkward hand positions and apply it to the image below for F1, F2, and F3?
I don't get the orientation of the thumb and how that dictates direction. In the first example for for F1 my thumb is pointed towards me to the right, F2 my thumb is pointed away from me, and F3 it is pointed towards me to the left. I dont get how this Shows me how F1 is clockwise, F2 counter, and F3 counter
Also in this example I would have thought all of the forces are counterclockwise except D but they aren't, Help! 😕
Best Answer
There are multiple ways to think about the right hand rule, the most popular are outlined here.
The one I find myself using the most is the "right hand grip rule". In your case, this would mean pointing your hand in the direction of r and then curling your fingers towards F, causing your thumb to point in the direction of the resulting vector (also the direction of the cross product of r and F).
Using the right hand grip rule for the torque due to F1, you can see that your fingers are curling in a clockwise direction and thus the torque about the center is in the direction of your thumb (into the page for F1, out of the page for F2 and F3).
You could also go the other way and give the direction of rotation based on a torque vector using the same rule... thumb points in the direction of the torque vector and your curled fingers will show the direction of rotation.
Hope this helps, and keep those wrists limber!!