Problem $6\mathrm{.}10.$ Let $$:$R{R}^{3}be$ defined $by$

$(t)=($:$3t-t^3,3t^2,3t+t^3$:$)$

Find:

$(a)$ The speed $of.$

$(b)$ The unit tangent vector $to.$

$(c)$ The curvature $of.$