consider vectors $u$ and $v.$

$u=7i+4k,v=4j+8k$

$($a$)$ Find the vector projection $w=pro{j}_{u}v$ of vector $v$ onto vector $u.$ Express your answer in component form.

$w=$

$$

$($b$)$ Find the scalar projection $com{p}_{u}v$ of vector $v$ onto vector $u.$

$com{p}_{u}v=$

$$