2nd ... note the curve equation is incorrect.
should be $x=(y-1)^2+1 \implies y = \sqrt{x-1}+1$ for the upper branch of the parabola
alternatively, you could translate both graphs such that the parabola vertex is at the origin, $x=y^2$, with the line having the equation $y = 2-x$ and rotating the shaded region about $y=-1$
I'm reviewing Meirovitch's "Methods of Analytical Dynamics," and I don't understand the commutation of the derivative from r to dr:
$$
\mathbf{F} \cdot d\mathbf{r} = m \ddot{\mathbf{r}} \cdot d\mathbf{r} = m\mathbf{\dot{r}} \cdot d\mathbf{\dot{r}}
$$