#### 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

See Property 5 of the cross product (page 714)
${\bf w}={\bf u}\times{\bf 0}={\bf 0}$
(zero vector has length 0 and no direction)
${\bf v}\times{\bf u}=-{\bf w}=(-{\bf 0})={\bf 0}$
${\bf u}\times{\bf v}$ has length $0$ and no direction
${\bf v}\times{\bf u}$ has length $0$ and no direction