The United States generates and uses about 71 quads of energy each year, and its renewable sources generate about 40 GW. If the renewable sources are generating power about a third of the time, what fraction of its energy usage is based on renewable sources?

Compute the pressure drop of 30°c air flowing with a mean velocity of 8 m/s in a circular sheet-metal duct 300 mm in diameter and 15 m long. use a friction factor, f 0.02, and pair = 1.1644 kg/m a. 37.26 pa b. 25.27 pa n c. 29.34 pa d. 30.52 pa

Ahe-xe mixture containing a 0.75 mole fraction of helium is used for cooling electronics in an avionics application. at a temperature of 300 k and atmospheric pressure, calculate the mass fraction of helium and the mass density, molar concentration and molecular weight of the mixture. if the cooling capacity is 10 l, what is the mass of the coolant?

The process in which the system pressure remain constant is called a)-isobaric b)-isochoric c)-isolated d)-isothermal