I'm trying to understand how to determine the sign (+/-) of a given couple. In the sample problem below it shows the 30 lb couple (on the zy-plane) having a negative value for it's force. Is this found by using the RHR? And if so, in which direction do I orient my hand? In the positive direction of the axis it's parallel to?
[itex]M = Fd[/itex]
Right Hand Rule
The Attempt at a Solution
I tried to depict the two orientations inside of the picture above.
Thank you for any help / feedback is appreciated.