Pressurized steam at 460k flows through a long, thin walled pipe of 0.5m diameter. the pipe is enclosed in a concrete casting that is of a square cross section and 1.5 m on a side. the axis of the pipe is centered in the casing, and the outer surfaces of the casing are maintained at 350k. determine the heat loss per unit length of pipe.

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?