单项选择题
A.fill the unit with saltwater B.fill the unit with de-scaling compound C.completely drain the unit D.tightly seal the unit to exclude air
A distinguishing feature of an educator, when compared ...
单项选择题A distinguishing feature of an educator, when compared to other pumps, is the （）.
A.dischargeendbeingsmallerthanthesuctionend B.smallsizeofimpeller C.lackofmovingparts D.easeatwhichthewearingringsmaybechanged
The heat required to change a substance from a liquid t...
单项选择题The heat required to change a substance from a liquid to a gas without experiencing a temperature change is defined as the latent heat of （）.
A.fusion B.vaporization C.sublimation D.condensation
Which of the processes listed consumes the greatest amo...
单项选择题Which of the processes listed consumes the greatest amount of power while producing the greatest amount of heat?（）
A.Overcoming sliding friction B.Overcoming rolling friction C.Overcoming fluid friction D.Overcoming oil wedge friction
