MCQ
If $\overrightarrow{ A }=(2 \hat{ i }+3 \hat{ j }-\hat{ k }) \;m$ and $\overrightarrow{ B }=(\hat{ i }+2 \hat{ j }+2 \hat{ k })\; m$. The magnitude of component of vector $\overrightarrow{ A }$ along vector $\vec{B}$ will be $......m$.
  • $2$
  • B
    $1$
  • C
    $3$
  • D
    $4$

Answer

Correct option: A.
$2$
a
$\overrightarrow{ A }=(2 \hat{ i }+3 \hat{ j }-\hat{ k }) m \text { and } \overrightarrow{ B }=(\hat{ i }+2 \hat{ j }+2 \hat{ k }) m$

Component of $\overrightarrow{ A }$ along $\overrightarrow{ B }=\overrightarrow{ A } \cdot \hat{ B }$

$=\frac{\overrightarrow{ A } \overrightarrow{ B }}{|\overrightarrow{ B }|}$ $=\frac{2+6-2}{\sqrt{1^{2}+2^{2}+2^{2}}}$

$=\frac{6}{3}=2$

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