Ahot air balloon (approx. as a sphere of diameter 10 m) is to lift a basket load of 2670 n. pair 0.2871 kg/m', rair 0.2871 kj/kg k. to what temperature must the inside air be heated in order to achieve liftoff.

For the closed feedwater heater below, feedwater enters state 3 at a pressure of 2000 psia and temperature of 420 °f at a rate of ix10 ibhr. the feedwat extracted steam enters state 1 at a pressure of 1000 psia and enthalpy of 1500 btu/lbm. the extracted er leaves at an enthalpy of 528.7 btu/lbm steam leaves as a saturated liquid. (16) a) determine the mass flow rate of the extraction steam used to heat the feedwater (10) b) determine the terminal temperature difference of the closed feedwater heater