Calculate: An object’s weight is determined by its mass (m) and the acceleration due to gravity (g) affecting that object: w = mg. On Earth, g = 9.8 m/s 2 . What are the masses (in kilograms) of the three objects on the Gizmo? (Note: 1 N = 1 kg  m/s 2 )

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.

If the ama of the inclined plane below is 2, calculate the ima and efficiency. ima = efficiency =

If we relied solely on the nonrenewable resources found in the u.s., which one would we run out of first at current usage levels? a. natural gas b. oil c. uranium d. coal