Scalar product using right hand rule ?

[goldfish9776]

Homework Statement

Refer to solution II , the author used the scalar analysis( dot product) to get the direction of moment ...IMO , this is incorrect ... Only cross product can be determined this way . correct me if I'm wrong .

Homework Equations

The Attempt at a Solution

 

[axmls]

No, the solution is correct. The value of a coupled moment is just equal to the magnitude of one of the forces times the perpendicular distance between them.

 

[goldfish9776]

No, the solution is correct. The value of a coupled moment is just equal to the magnitude of one of the forces times the perpendicular distance between them.

how can the direction of moment(scalar analysis) determined using the right hand grip rule ?