A) 42
B) 56
C) 38
D) 74
Correct Answer: A
Solution :
\[\vec{A}\times \vec{B}=\left| \begin{matrix} {\hat{i}} & {\hat{j}} & {\hat{k}} \\ 2 & 1 & -3 \\ 0 & 12 & -2 \\ \end{matrix} \right|\] \[=\hat{i}(-2+36)-\hat{j}(-4-0)+\hat{k}(24-0)\] \[=34\hat{i}+4\hat{j}+24\hat{k}\] \[|\vec{A}\times \vec{B}|=\sqrt{1156+16+576}\] \[=41.81\approx 42\] Hence, the correction option is [a].You need to login to perform this action.
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