The position vector of a particle is deter

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The position vector of a particle is determined by the expression $\vec r = 3{t^2}\hat i + 4{t^2}\hat j + 7\hat k$ The distance traversed in first $10 \,sec$ is........ $m$

A

$500$

B

$300$

C

$150$

D

$100$
The position vector of a particle is determined by the expression $\vec r = 3{t^2}\hat i + 4{t^2}\hat j + 7\hat k$ The distance traversed in first $10 \,sec$ is........ $m$
$\vec r = 3{t^2}\hat i + 4{t^2}\hat j + 7\hat k$
at $t = 0$, ${\vec r_1} = 7\hat k$
at $t = 10\sec $, ${\vec r_2} = 300\hat i + 400\hat j + 7\hat k$,
$\overrightarrow {\Delta r} = {\vec r_2} - {\vec r_1} = 300\hat i + 400\hat j$
$|\overrightarrow {\Delta r} |\, = \,|{\vec r_2} - {\vec r_1}|\, = \sqrt {{{(300)}^2} + {{(400)}^2}} = 500m$