\(v_{x}=8-6 t\)
\(\left(\mathrm{v}_{\mathrm{x}}\right)_{\mathrm{t}=1}=2 \hat{\mathrm{i}}\)
\(y=5-8 t^{3}\)
\(\mathrm{v}_{\mathrm{y}}=-24 \mathrm{t}^{2}\)
\(\left(v_{y}\right)_{t=1}=-24 \hat{j}\)
\(\mathrm{Now}\)
\(\sqrt{\mathrm{v}}=\sqrt{(24)^{2}+(2)^{2}}=\sqrt{580}\)
\(\therefore \mathrm{v}=580 \mathrm{m}^{2} / \mathrm{s}^{2}\)