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# Speed of Accelerating Object

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An object moving in the $xy$-plane has velocity ${\bf v}(0)=2{\bf i}$ in an initial moment, then it starts to accelerate as described by the function:

$${\bf a}(t)= 2t{\bf i} + 3t^2 {\bf j}$$

If time is measured in seconds and distance is measured in meters, what will be the speed of this object two seconds later?

A

$100 \ m/s$

B

$4\sqrt{5} \ m/s$

C

$(t^2 +2) {\bf i} + t^3 {\bf j}$

D

$4\sqrt{10} m/s$

E

$10 \ m/s$