Answer
${\bf u}\times{\bf v}$ has length $0$ and no direction
${\bf v}\times{\bf u}$ has length $0$ and no direction
Work Step by Step
By property 5 (see "Properties of the Cross Product" box on p. 618)
${\bf w}={\bf u}\times{\bf 0}={\bf 0}$
(zero vector has length 0 and no direction)
By property 3,
${\bf v}\times{\bf u}=-{\bf w}=(-{\bf 0})={\bf 0}$
