(Solved): The position vector of an object at time \( t \) is given by: \[ \mathbf{r}=\left(a t^{3}-3 t^{2}\r ...

The position vector of an object at time \( t \) is given by: \[ \mathbf{r}=\left(a t^{3}-3 t^{2}\right) \mathbf{i}+\left(6 t^{2}-b t\right) \mathbf{j} \] Find the speed of the object at time \( t=5.1 \) for \( a=1.6 \) and \( b=1.1 \) Give your result to three decimal places.