3. A submarine can be assumed to have cylindrical shape with rounded nose. Assuming its length to be 50 m and diameter 5.0 m, determine the total power required to overcome boundary friction if it cruises at 8 m/s velocity in sea water at 20C (p = 1030 kg/m, v = 1 106 m/s). The average friction coefficient for a laminar boundary layer is C'f 1.328 Re- -0.5 and for a turbulent boundary layer is C = 0.074 Re-0.2. =