A galaxy is A. a name for the great variety of stars B. A large glowing ball of gas powered by nuclear energy C. A collection of a few hundred million to a few trillion or more stars, bound together by gravity D. another name for the universe E. a system consisting of one or a few stars orbited by planets, moons, and smaller objects

Which notation is used to represent an alpha particle? a. b. c. d.

If the new moon happens on january 15th, what shape will it be on february 6th?

4r-134a enters the condenser of a residential heat pump at 800 kpa and 50°c at a rate of 0.022 kg/s and leaves at 750 kpa subcooled by 3°c. the refrigerant enters the compressor at 200 kpa superheated by 4°c determine (a) the isentropic efficiency of the compressor, (b) the rate of heat supplied to the heated room, and (c) the cop of the heat pump. also, determine (d) the cop and rate of heat supplied to the heated room if this heat pump operated on the ideal vapor-compression cycle between the pressure limits of 200 and 800 kpa. (0.757, 4.37 kw, 5.12, 6.18, 3.91 kw)