Why does air move from solid land towards water during the night? A-Solid ground cools faster at night while water remains heat longer, warming the air above the water.

B- The ground retains the heat from the sun longer than the water.

C- The dry air over the land is heavier than the air over the water the contains more water vapor

D- gravity moves the air towards the water because water is lower than the land

The graph below represents the work done by a student while running up flights of stairs. determine the student's power output after 10 seconds: 1600 j/s 8000 j/s 160 j/s 800 j/s

As part of an industrial process, air as an ideal gas at 10 bar, 400k expands at steady state through a valve to a pressure of 4 bar. the mass flow rate of air is 0.5 kg/s. the air then passes through a heat exchanger where it is cooled to a temperature of 295k with negligible change in pressure. the valve can be modeled as a throttling process, and kinetic and potential energy effects can be neglected. (a) for a control volume enclosing the valve and heat exchanger and enough of the local surroundings that the heat transfer occurs at the ambient temperature of 295 k, determine the rate of entropy production, in kw/k. (b) if the expansion valve were replaced by an adiabatic turbine operating isentropically, what would be the entropy production? compare the results of parts (a) and (b) and discuss.

The junction rule describes the conservation of which quantity? note that this rule applies only to circuits that are in a steady state.