Methane flows in an adiabatic pipe with a diameter of 0.1 m that has a friction factor of 0.004. The inlet Mach number is 0.15, and the stagnation conditions are350 K and 300 kPa. What is the maximum length the pipe can have and still maintain these inlet conditions?

In the winter, in order to keep the classroom steadily at 68 f before 10 pm, heating with an average rate of 42,000 btu/hr is provided. assume the outdoor temperature maintains at 32°f, determine the electrical power (kw) required to (a) operate a reversible heat pump (b) operate a real heat pump with a cop (7) of 4.5 and (c) operate an electrical-resistance heater.