Question 1646Deck General70% to pass
You are using tackle number 3 as shown in illustration D029DG below to lift a weight of 120 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 D) 52 lbs.
To explain:
1) With tackle number 3, there are 3 parts supporting the load, so the effective weight of the 120 lb load is reduced by a factor of 3. This gives an effective load of 120 / 3 = 40 lbs.
2) Additionally, the problem states to include 10% of the weight for each sheave for friction. With 3 sheaves, this adds 30% to the effective load, for a total of 52 lbs (40 lbs + 30% of 40 lbs).
3) The other options are incorrect because they do not properly account for both the mechanical advantage of the tackle system and the friction losses in the sheaves.
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