P3.53 Consider incompressible flow in the entrance of a circular tube, as in Fig. P3.53. The inlet flow is uniform, u̟ = Uo. The flow at section 2 is developed

pipe flow. Find the wall drag force F as a function of (p1, P2, P, Uo, R) if the flow at section 2 is \text { (a) Laminar: } u_{2}=u_{\max }\left(1-\frac{r^{2}}{R^{2}}\right) \text { (b) Turbulent: } u_{2} \approx u_{\max }\left(1-\frac{r}{R}\right)^{1 / 7}