$4-25.$ The velocity profile for a fluid within the circular

pipe for fully developed turbulent flow is modeled using

Prandtl's one$-$seventh power law $u=U(\frac{y}{R}{)}^{\frac{1}{7}}.$ Determine

the average velocity for this case.

$4-26.$ The velocity profile for a fluid within the circular

pipe for fully developed turbulent flow is modeled using

Prandtl's one$-$seventh power law $u=U(\frac{y}{R}{)}^{\frac{1}{7}}.$ Determine

the mass flow of the fluid if it has a density $.$

Probs. $4-25/26$