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# A particle has velocity $v= 2\hat r+4 \hat j$ and acceleration $\overrightarrow{a}=0.1 \hat{i}+0.4 \hat j$ Find the speed after 10 seconds

$\begin{array}{1 1} (a) \;\sqrt{27} \\ (b) \;\sqrt{73}\\ (c) \;\sqrt{8} \\ (d) \;\sqrt{12}\end{array}$

$v= u+at$
$v= (2 \hat i +4 \hat j+(1 \hat {i}+4 \hat {j}) \times 10$
$\qquad= 3 \hat i +8 \hat j$
$| \overrightarrow{v}=\sqrt{3^2+8^2}$
$\qquad= \sqrt{73}$