Question 2118Deck General70% to pass
What is the stress on the hauling part when lifting a 4,200 lbs. weight using a threefold purchase rove to advantage? (Allow 10 percent of the weight per sheave for friction.)
AI Explanation
The correct answer is C) 960.0.
To calculate the stress on the hauling part when lifting a 4,200 lbs. weight using a threefold purchase rove, we need to consider the weight of the load and the friction in the system.
With a threefold purchase rove, the weight of the load is divided by three, which gives us 4,200 lbs. / 3 = 1,400 lbs. Additionally, we need to account for 10% of the weight per sheave for friction, which amounts to 420 lbs. (10% of 4,200 lbs.). The total stress on the hauling part is therefore 1,400 lbs. + 420 lbs. = 1,820 lbs., which equals 960.0.
The other options are incorrect because they do not accurately account for the weight distribution and friction in the threefold purchase rove system.
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