Air of density 0.082 lbm/ft3 enters the duct of an air-conditioning system at a volume flow rate of 450 ft3/ min. if the diameter of the duct is 17.2 in, determine the velocity of the air at the duct inlet and the mass flow rate of air.

During a steady flow process, the change of energy with respect to time is zero. a)- true b)- false

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?

The maximum shear stress and maximum flexural stress occur at the same location along a beam subjected to a non-uniform bending load. a)-trune b)- false