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.)
Answer (1)
The stress on the hauling part when lifting a 4,200 lbs. weight using a threefold purchase rove to advantage is 1,818 lbs.Data GivenLoad = 4,200 lbsSheaves = 3 Total friction = 3 × 10% = 30% Effective mechanical advantage = 3 ÷ 1.3 = 2.31 Stress = 4,200 ÷ 2.31 Stress = 1,818 lbs
