$($solve it for fluid mechanics$)$ Water flows downward in a circular crosssectional pipe with diameter D and radius R $,$ as shown in Fig. Prob. $5.$ At section $(1),$ the velocity profile over the cross$-$sectional area is uniform as uc and pressure is p $1,$ At section $(2)$ and $(3),$ the axial velocity profile is parabolic. That is$,$ the pressures are p $2$ and p $3$ respectively. Please find $(20$Points$)$: $1)$ the volume flowrate at section $1,2$ and $3.$

the average velocity at section $2$ and $3$ respectively. The momentum flux at section $1,2$ and $3$ respectively. The friction force exerted by the pipe to wall between section $1$ and $2.$ The friction force exerted by the pipe to wall between section $2$ and $3.$ The wall shear stress $($shear stress on the pipe wall, or friction force per area$)$ between section $2$ and $3.$