Answer
$|\overrightarrow{u}|=10$;
$\overrightarrow{u} \cdot \overrightarrow{u}=100$;
$\overrightarrow{u} \cdot \overrightarrow{v}=-30$
Work Step by Step
Here, we have $u=(0,10); v=(5,-3)$
$|\overrightarrow{u}|=\sqrt {(0)^2+(10)^2}=\sqrt {100}=10$;
$\overrightarrow{u} \cdot \overrightarrow{u}=(0)^2+(10)^2=100$;
$\overrightarrow{u} \cdot \overrightarrow{v}=0(5)+10(-3)=0-30$
or, $\overrightarrow{u} \cdot \overrightarrow{v}=-30$
