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【简答题】
小明观察到电风扇、落地灯等一个大而重的底座 , 使它们不易翻倒。进而他提出猜想 : 物体的稳定程度可能与物体重心高低有关。 为了验证猜想 , 他将三块相同的橡皮泥分别固定在三个相同的圆柱体的底部、中部和上部 , 其重心位置如图甲所示 , 然后小心地推翻圆柱体 , 观察圆柱体刚好翻倒时转过的角度 θ ( 如图乙 ) 并记录在下表中。 实验次数 1 2 3 重心高低 低 中 高 圆柱体刚好翻倒时转过的角度 θ 大 较大 小 稳定程度 大 较大 小 (1) 圆柱体刚好翻倒时转过的角度 θ 越小 , 反映圆柱体的稳度越 ( 选填 “ 大 ” 或 “ 小 ” ) 。 (2) 分析表中的信息可知 : 物体的重心越 , 其稳度越大。 (3) 依据以上结论 : 卡车装货物时 , 把重的货物装在 ( 选填 “ 上 ” 或 “ 下 ” ) 层 , 可使卡车不易翻倒。
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A.
毛细血管血压升高
B.
血浆胶体渗透压降低
C.
毛细血管血压降低
D.
毛细血管通透性增加
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【单选题】Which of the conditions listed could cause the cylinder relief valves on a large, low-speed, propulsion diesel engine to lift?
A.
Plugged injector nozzles
B.
Excessive fuel injection
C.
Very late injection timing
D.
Incorrect crankshaft clearance
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【单选题】Most hydraulic steering gears are fitted with relief valves which .
A.
function when the rudder is amidships
B.
relieve excess whip pressure from the hydraulic oil system
C.
protect the piping assembly from external rudder shock
D.
relieve excessive telemotor pressure
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【单选题】Cargo pump relief valves are piped to the ______．
A.
cargo pump pressure gauges
B.
crossover lines interconnecting two pumps
C.
suction side of pumps
D.
atmosphere through pump vents
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【判断题】Relief valves are used for liquids; safety valves are used for gases
A.
正确
B.
错误
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【单选题】在电感元件的正弦交流电路中,若电压的有效值一定,则当频率增大时,电流将( )。
A.
增大
B.
减小
C.
不变
D.
不确定
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【单选题】Blow-off of the relief valves of the engines cylinders may be caused by _____.
A.
too low lead
B.
water in fuel
C.
too tight spring
D.
leakage
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【简答题】变频器参数设置中,P4表示( )P5表示( )P6表示( )
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【单选题】What is the purpose of pressure-vacuum relief valves ________．
A.
Regulation of discharge pressure from cargo pumps
B.
Maintaining constant velocity in cargo lines
C.
Regulation of suction head on cargo pumps
D.
To maintain a tank or void at atmospheric pressure
查看完整题目与答案
【判断题】Relief valves are used for gases; safety valves are used for liquids.
A.
正确
B.
错误
查看完整题目与答案
相关题目：
【单选题】肾脏疾病时，排出大量蛋白质，导致水肿，其原因是
A.
毛细血管血压升高
B.
血浆胶体渗透压降低
C.
毛细血管血压降低
D.
毛细血管通透性增加
查看完整题目与答案
【单选题】Which of the conditions listed could cause the cylinder relief valves on a large, low-speed, propulsion diesel engine to lift?
A.
Plugged injector nozzles
B.
Excessive fuel injection
C.
Very late injection timing
D.
Incorrect crankshaft clearance
查看完整题目与答案
【单选题】Most hydraulic steering gears are fitted with relief valves which .
A.
function when the rudder is amidships
B.
relieve excess whip pressure from the hydraulic oil system
C.
protect the piping assembly from external rudder shock
D.
relieve excessive telemotor pressure
查看完整题目与答案
【单选题】Cargo pump relief valves are piped to the ______．
A.
cargo pump pressure gauges
B.
crossover lines interconnecting two pumps
C.
suction side of pumps
D.
atmosphere through pump vents
查看完整题目与答案
【判断题】Relief valves are used for liquids; safety valves are used for gases
A.
正确
B.
错误
查看完整题目与答案
【单选题】在电感元件的正弦交流电路中,若电压的有效值一定,则当频率增大时,电流将( )。
A.
增大
B.
减小
C.
不变
D.
不确定
查看完整题目与答案
【单选题】Blow-off of the relief valves of the engines cylinders may be caused by _____.
A.
too low lead
B.
water in fuel
C.
too tight spring
D.
leakage
查看完整题目与答案
【简答题】变频器参数设置中,P4表示( )P5表示( )P6表示( )
查看完整题目与答案
【单选题】What is the purpose of pressure-vacuum relief valves ________．
A.
Regulation of discharge pressure from cargo pumps
B.
Maintaining constant velocity in cargo lines
C.
Regulation of suction head on cargo pumps
D.
To maintain a tank or void at atmospheric pressure
查看完整题目与答案
【判断题】Relief valves are used for gases; safety valves are used for liquids.
A.
正确
B.
错误
查看完整题目与答案