The velocity of a particle is given as \( \vec{v}=-x\,\hat{\imath}+2y\,\hat{\jmath}-z\,\hat{k}\ \text{m}/\text{s} \). The magnitude of acceleration at point \( (1,2,4) \) is ______ \( \text{m}/\text{s}^{2} \).
\( \sqrt{6} \)
\( 9 \)
\( \sqrt{33} \)
\( 0 \)