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A particle has initial velocity $(2\hat i + 3\hat j)$ and acceleration $(0.3\hat i + 0.2\hat j)$. The magnitude of velocity after 10 seconds will be
A
9 units
B
$9\sqrt2$ units
C
$5\sqrt2$ units
D
5 units
Detailed Solution
$\vec v = \vec u + \vec at$
$= (2\hat i + 3\hat j) + (0.3\hat i + 0.2\hat j)\times10$
$= (2 + 3)\hat i + (3 + 2)\hat j = 5\hat i + 5\hat j$
$|\vec v| = \sqrt{5^2 + 5^2} = 5\sqrt2$ units
$= (2\hat i + 3\hat j) + (0.3\hat i + 0.2\hat j)\times10$
$= (2 + 3)\hat i + (3 + 2)\hat j = 5\hat i + 5\hat j$
$|\vec v| = \sqrt{5^2 + 5^2} = 5\sqrt2$ units