# Particle in 3-D

Level pending

A particle moves in a $$3$$-dimensional space so that its acceleration vector at any time $$t>0$$ is $$\boldsymbol{a}(t) = \boldsymbol{i} + 2\ \boldsymbol{j}$$ and its initial velocity is $$\boldsymbol{v}(0) = \boldsymbol{k}$$. If $$S$$ is the speed of the particle at $$t = 2$$, what is the value of $$S^2$$?

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