MCQ
A vector $\vec a = 2\hat i + 3\hat j + 7\hat k$ is there in right handed rectangular coordinate system. The coordinate system is rotated about $z-$ axis from positive $x$ to positive $y-$ axis through angle $\pi /2$ , then new components of $\vec a$ will be 
  • A
    $(2, 3, 7)$
  • B
    $(-2, -3, 7)$
  • C
    $(3, -2, -7)$
  • $(3, -2, 7)$

Answer

Correct option: D.
$(3, -2, 7)$
d
There will be no change in $z$ - component

$\therefore $ New component are $(3,-2,7).$

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