Given the Hagen$-$Poiseuille Equation for the velocity of a fluid in a horizontal tube of radius R and lenght L: a$)$ Where is the velocity maximum? b$)$ What is the maximum velocity? R$=40$ mm$,$ L$=30,$ P$0-$P$1=20$kPa, $=14cP,v=\frac{P0-P1}{L}*\frac{R^2}{4}*1-\frac{r^2}{R^2}$