Answer
Maximum length of the vector $u \times v=15$
Minimum length of the vector $u \times v$$=0$
Work Step by Step
Length of the vector $u \times v= || u \times v||=|| u|| \times || v||| sin \theta|$
$u \times v= || u \times v||=|| u|| \times || v|| |sin \theta|= 5 \times 3 |sin \theta|=15 sin \theta$
Maximum of $|sin \theta|$=1 and minimum of $|sin \theta|$=0
Thus,
Maximum length of the vector $u \times v=15 \times 1=15$
Minimum length of the vector $u \times v$$= 15 \times 0 =0$