Example 4.2.1. Sign Conventions.
For each scalar component, determine whether the moment is clockwise or counterclockwise, and apply the right-hand rule to determine the direction of the corresponding moment vector.
Answer.
or CCW or CW or CW or CCW
Solution.
By the right-hand rule, counterclockwise moments in the - plane are vectors that point in the direction. The corresponding scalar component has a positive sign. Clockwise moments point in the direction and have a negative sign.
is positive, so it is CCW and the vector points in the direction. is negative, so it is CW and the vector points direction.- The arrow on
establishes the positive direction as CW. A positive scalar component means that the direction is CW and the vector points in the direction. - The arrow on
establishes the positive direction as CW, but the negative sign on the scalar component means that the actual moment is CCW. The vector points in the direction.