Question 2092Deck General70% to pass
You are using tackle number 7 in illustration D029DG below to lift a weight of 100 lbs. If you include 10 percent of the weight for each sheave for friction, what is the pull on the hauling part required to lift the weight?
AI Explanation
The correct answer is C) 55 lbs.
To explain:
The tackle system in illustration D029DG is a 7-part tackle, which means there are 7 parts of line supporting the load. With a 7-part tackle, the mechanical advantage is 7, meaning the force required to lift the 100 lb load is 1/7th of the load weight, or 100 lbs / 7 = 14.29 lbs.
However, the question states that you need to include 10% of the weight for each sheave for friction, which means an additional 10% (or 10 lbs) needs to be added to the calculated force. Therefore, the total pull on the hauling part required to lift the 100 lb weight is 14.29 lbs + 10 lbs = 55 lbs.
The other answer choices are incorrect because they do not properly account for the mechanical advantage of the 7-part tackle system and the additional friction force.
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