Two plane disks each 1.25 m in diameter are parallel and directly opposite each other. they are separated by a distance of 0.5 m. disk 1 is heated by electrical resistance to 833.3 k. both disks are insulated on all faces except the two faces directly opposite each other. assume that the surroundings emit no radiation and that the disks are in space. calculate the temperature of disk 2 at steady state and also the electrical energy input to disk 1. (hint: the fraction of heat lost from area number 1 to space is 1 – f12.)

Liquid flows at steady state at a rate of 2 lb/'s through a pump, which operates to raise the elevation of the liquid 100 ft from control volume inlet to exit. the liquid specific enthalpy at the inlet is 40.09 btu/lb and at the exit is 40.94 btub. the pump requires 3 btu/s of power to operate. if kinetic energy effects are negligible and gravitational acceleration is 32.174 tt/s, the heat transfer rate associated with this steady state process is most closely 1)-2,02 btu/s from the liquid to the surroundings 2)-3.98 btu/s from the surroundings to the liquid. 3)-4.96 btu/s from the surroundings to the liquid. 4)-1.04 btu/s from the liquid to the surroundings.