Use the dot product to find the magnitude of u. $\mathbf { u } = 4 \mathbf { j }$
A)5
B)6
C)4
D)7
E)8

Name: Use the dot product to find the magnitude of u. $\mathbf { u } = 4 \mathbf { j }$ A)5 B)6 C)4 D)7 E)8
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Question

Use the dot product to find the magnitude of u.  $\mathbf { u } = 4 \mathbf { j }$  
A)5
B)6
C)4
D)7
E)8

Quizplus · Accepted Answer

The magnitude of a vector $\mathbf{u} = a\mathbf{i} + b\mathbf{j} + c\mathbf{k}$ is given by $\sqrt{a^2 + b^2 + c^2}$. For $\mathbf{u} = 4\mathbf{j}$, $a = 0$, $b = 4$, and $c = 0$, so the magnitude is $\sqrt{0^2 + 4^2 + 0^2} = \sqrt{16} = 4$.

Use the Dot Product to Find the Magnitude of U u=4j\mathbf { u } = 4 \mathbf { j }u=4j

Use the Dot Product to Find the Magnitude of U $\mathbf { u } = 4 \mathbf { j }$