Question 457Deck General70% to pass
You are lifting a one-ton weight with a swinging boom. When comparing the stresses in the rig with the boom at 20° to the horizontal to the stresses when the boom is at 60° to the horizontal, which statement is TRUE?
AI Explanation
The correct answer is A) The stress on the masthead fairlead for the topping lift is greater at 20°.
As the boom angle decreases from 60° to 20°, the tension in the topping lift increases significantly. This is because the topping lift must support a greater component of the weight load as the boom angle becomes more horizontal. The increased tension in the topping lift translates to greater stress on the masthead fairlead where the topping lift is routed.
The other answer choices are incorrect because: B) The stress on the heel block is actually greater at the 20° angle due to the increased weight load; C) The thrust on the boom is less at 20° as the weight load is more directly applied; and D) The stress on the topping lift is greater at 20°, not 60°.
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