2 a) Which of the following statements is true? i) Sound is produced in a vibrating environment. ii) Sound can easily propagate in a vacuum. iii) You can talk to your friend on the Moon. iv) Sound is propagated in the air by successive compressions and thinning of the air. V) Too much noise can damage the ears. b) For any statement that is not correct, say what is wrong. Rewrite the statement correctly. 3 Native Americans could hear horses approaching by bringing their ears to the ground. Explain why?

True or false when elements combine to form a mixture, the resulting chemical properties may be very different from those of the elements that make it.

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)

To a of 4 x hz is 1. 0. mm nm nm