Question
Question: What is the unit vector perpendicular to the following vectors \(2\widehat{i} + 2\widehat{j} - \wide...
What is the unit vector perpendicular to the following vectors 2i+2j−k and 6i−3j+2k
A
517i+10j−18k
B
517i−10j+18k
C
517i−10j−18k
D
517i+10j+18k
Answer
517i−10j−18k
Explanation
Solution
A=2i+2j−kand B=6i−3j+2k
C=A×B=(2i+2j−k)×(6i−3j+2k)
\widehat{i} & \widehat{j} & \widehat{k} \\ 2 & 2 & - 1 \\ 6 & - 3 & 2 \end{matrix} \right| = \widehat{i} - 10\widehat{j} - 18\widehat{k}$$ Unit vector perpendicular to both $\overrightarrow{A}$ and $\overrightarrow{B}$ $$= \frac{\widehat{i} - 10\widehat{j} - 18\widehat{k}}{\sqrt{1^{2} + 10^{2} + 18^{2}}} = \frac{\widehat{i} - 10\widehat{j} - 18\widehat{k}}{5\sqrt{17}}$$