On cargo booms，preventers are（）.

A、auxiliary guys

B、extra fair leads

C、steel bands

D、stops

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更多“On cargo booms，preventers are（）.”相关的问题

第1题

[单选题] For a given weight of cargo，the stress on the heel block of a cargo boom（）.

A、increases as the cargo closes the head while hoisting B、increases if the cargo runner is doubled up C、decreases as the boom is topped to a greater angle D、is determined by the thrust stresses on the boom

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第2题

[单选题] With a given load on the cargo hook，the thrust on a cargo boom（）.

A、increases as the angle to the horizontal increases B、increases as the angle to the horizontal decreases C、is greatest at an angle of 45° and decreases as the boom is raised or lowered D、is least at an angle of 45° and increases as the boom is raised or lowered

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第3题

[单选题] Stress on the topping lift of a swinging boom can be reduced by（）.

A、rigging a back stay B、raising the boom C、increasing the mechanical advantage of the cargo purchase D、taking all slack out of the preventer

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第4题

[单选题] With a given load on the cargo hook，tension in a single span topping lift（）.

A、increases as the boom's angle to the horizontal increases B、is at a maximum when the boom is at a 45° angle to the horizontal C、increases as the boom's angle to the horizontal decreases D、decreases as the boom's angle to the horizontal decreases

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第5题

[单选题] The （）(浮吊) can float on water used to load and unload the cargo.

A、floating crane B、jumbo boom C、union purchase D、crane

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第6题

[单选题] The safe working load for the assembled cargo gear and the minimum angle to the horizontal for which the gear is designed shall be marked on the（）.

A、deck B、head of the boom C、heel of the boom D、mast or king post

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第7题

[单选题] A （）is used for lifting long heavy cargo.

A、derrick B、crane C、jumbo boom D、boom