单项选择题
Because the top of the connecting rod swings about the pin and changes direction each time the piston reaches mid-stroke, the relative speed between bearing and pin at mid-stroke is zero, （）to a maximum as the piston approaches top or bottom dead center and then （） back to zero again as the piston approaches mid-stroke and the connecting rod changes direction.
A.accelerates；decelerates
B.accelerates；accelerates
C.decelerates；decelerates
D.decelerates；accelerates
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相关考题
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单项选择题
The slippers run （） in the crosshead guides as the piston and rod are （）and prevent the top of the connecting rod from moving sideways.
A.up and down；reciprocating
B.up and down；rotating
C.back and forth；reciprocating
D.back and forth；rotating -
单项选择题
The connecting rob is fitted between the crosshead and the crankshaftIt transmits the firing force, and together with the crankshaft convert the （） motion to a （） motion.
A.rotary；reciprocating
B.up and down；fore and aft
C.fore and aft；up and down
D.up and down；rotary -
单项选择题
The （） of the semi-built method of the construction crankshaft is that by making the two webs and crankpin from a single forging the grain flow in the steel follows the web round into the crankpin and back down the other web.
A.advantages
B.disadvantages
C.power advantages
D.power disadvantages
