| Practice Problem 1-1 |
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Given: Large wooden cylindrical posts, some up to ~30 ft long and 30 inches in diameter, serve as benches on Stearn's Wharf in Santa Barbara. . Req'd: The size (capacity) of the crane required to place the benches. Assume the cranes come in 2-ton (4,000 lb) increments. |
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Solution: From Table 3 the density of wood is 40 pfc (lb/ft3). The volume of the post is V = (pD2/4)*L V = (p2.5 ft2/4)*30 ft = 147.3 ft3 The weight of the post is W = Volume x Density = 147.3 ft3 * 40 pfc = 5890 lb ~6000 lb = 3 tons Since the cranes come in increments of 2-tons, the required crane capacity is 4 tons. |
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