单项选择题
A.altostratus B.stratus C.cumulus D.cirrus
A tank 36 ft. by 36 ft. by 6 ft. is filled with water t...
单项选择题A tank 36 ft. by 36 ft. by 6 ft. is filled with water to a depth of 5 ft. If a bulkhead is placed in the center of the tank running fore-and-aft along the 36-foot axis，how will the value of the moment of inertia of the free surface be affected?（）
A.The moment of inertia would remain unchanged B.The moment of inertia would be 1/4 its original value C.The moment of inertia would be 1/2 the original value D.None of the above
A tackle is “two blocked” when the blocks are（）.A.equal...
单项选择题A tackle is “two blocked” when the blocks are（）.
A.equally sharing the load B.jammed together C.as far apart as possible D.rove to the highest mechanical advantage
A swift current occurring in a narrow passage connectin...
单项选择题A swift current occurring in a narrow passage connecting two large bodies of water，which is produced by the continuously changing difference in height of tide at the two ends of the passage，is called a（）.
A.hydraulic current B.rectilinear current C.rotary current D.harmonic current
