In a two-dimensional statics problem involving finding a moment about a point, I don't understand how the result is either in the positive/negative z direction.(adsbygoogle = window.adsbygoogle || []).push({});

I realize moments are found by the cross product, and the cross product requires the answer to be perpendicular to the plane that the two vectors form.

If I look down at the surface of my desk and take that to be an x-y plane. a pencil laying on the plane is held stationary at it's left end, and the right end is made to rotate clockwise. This tells me that I can expect my moment to be in the negative z direction (say, going down through the surface of the desk). This makes no sense to me, what concept am I missing here?

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# What simple concept am I missing about moments?

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