单项选择题
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
The degree to which the viscosity of an oil will change...
单项选择题The degree to which the viscosity of an oil will change with a change in temperature is indicated by the （）.
A.weight designation B.viscosity index C.pour point D.thermal change value
