The negative value suggests that a moment that tends to rotate a body clockwise around an axis should have a negative sign. However, the actual sign depends on the choice of the three axes e x , e y , e z {\displaystyle \mathbf {e} _{x},\mathbf {e} _{y},\mathbf {e} _{z}} . For instance, if we choose another right handed coordinate system with E x = e x , E y = − e z , E z = e y {\displaystyle \mathbf {E} _{x}=\mathbf {e} _{x},\mathbf {E} _{y}=-\mathbf {e} _{z},\mathbf {E} _{z}=\mathbf {e} _{y}} , we have