Rectangular ditch having a cross-sectional area of 24 sq ft (2.2 m2) is being excavated in clay. The soil’s angle of repose is 35° and its swell is 30%. Find the height and width
of the triangular spoil bank that will result from the trench excavation.

At steady state, air at 200 kpa, 325 k, and mass flow rate of 0.5 kg/s enters an insulated duct having differing inlet and exit cross-sectional areas. the inlet cross-sectional area is 6 cm2. at the duct exit, the pressure of the air is 100 kpa and the velocity is 250 m/s. neglecting potential energy effects and modeling air as an 1.008 kj/kg k, determine ideal gas with constant cp = (a) the velocity of the air at the inlet, in m/s. (b) the temperature of the air at the exit, in k. (c) the exit cross-sectional area, in cm2