Explain briefly what is meant by fully developed laminar flow. The velocity u at any radius r in fully developed laminar flow through a straight horizontal pipe of internal radius ro is given by u= (1/4)(ro2-r2)dp/dx dp/dx is the pressure gradient in the direction of flow and u is the dynamic viscosity. Show that the pressure drop over a length L is given by the following formula. Ap=32Lum/D The wall skin friction coefficient is defined as Cf=2to/( pum). Show that C= 16/Re where Re = pumD/ and p is the density, um is the mean velocity and to is the wall shear stress.