A rectangular channel is 400 ft wide and the normal depth is 10 ft with an average velocity of 5 fps. A roadway is to cross the channel using a bridge with equal encroachments from each side. Determine the water depth at Section 2 and 3 for bridge lengths (B) of 100, 150 and 200 ft. What is the maximum length of bridge that will cause critical depth to occur in the constriction? Neglect headloss and channel slope.

Asolid cylinder is concentric with a straight pipe. the cylinder is 0.5 m long and has an outside diameter of 8 cm. the pipe has an inside diameter of 8.5 cm. the annulus between the cylinder ad the pipe contains stationary oil. the oil has a specific gravity of 0.92 and a kinematic viscosity of 5.57 x 10-4 m2/s. most nearly, what is the force needed to move the cylinder along the pipe at a constant velocity of 1 m/s?