The diagram below shows two vectors u,v such that lies in the positive quadrant of the xy-plane (meaning the x and y coordinates are both positive) and ||u|| =2 and ||v|| lies on the positive portion of the z -axis and ||v||=3. If \(\mathbf u\times\mathbf v = \begin{pmatrix} a\\b\\c \end{pmatrix},\) what is the sign of a and what is \(\|\mathbf u\times\mathbf v\|?\)