Question

Find the value of $10b$ , if a unit vector is represented as $\left(\right.0.8\hat{i}+b\hat{j}+\sqrt{0 . 2}\hat{ k}\left.\right)$ .

Answer 1

Unit vector $(0.8 \hat{\imath}+b \hat{\jmath}+\sqrt{0.2} \widehat{k})$
$\therefore \sqrt{(0.8)^2+b^2+(\sqrt{0.2})^2}=1 $
$\therefore 0.64+b^2+0.2=1 $
$\therefore b^2=1-0.84=0.16$
$\therefore b=0.4$