How do you compute the dot product to find the magnitude of u=6j?

Jan 8, 2017

$| | \vec{u} | | = 6$

Explanation:

It should be absolutely obvious that $\vec{u} = 6 \hat{j}$ represents a vector pointing up along $O y$ of $6$ units, so theretofore $| | \vec{u} | | = 6$.

We can show this using the dot product using the fact that:

$| | \vec{u} | | = \sqrt{\vec{u} \cdot \vec{u}}$

To get

$| | \vec{u} | | = \sqrt{\left(6\right) \left(6\right)} = \sqrt{{6}^{2}} = 6$