A hot air balloon has a mass of 300 k gincluding the basket. The hot air inside the balloon weighs 17,000 N. Determine the maximum load that the balloon is able to lift displaces 25,000 N of cold air. Use 10 m/s2 for gravity.

To create electromagnetic induction, which of the following has to move? a. a wire b. a magnet c. a transformer d. either a or b

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.

Which branches of natural science include the study of an organism that lived 10 million years ago