單項(xiàng)選擇題

A distinguishing feature of an educator, when compared to other pumps, is the （）.

A.dischargeendbeingsmallerthanthesuctionend
B.smallsizeofimpeller
C.lackofmovingparts
D.easeatwhichthewearingringsmaybechanged

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單項(xiàng)選擇題

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

單項(xiàng)選擇題

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