A fully loaded wheeled scraper (Model #: 615C) must travel d…

A fully loaded wheeled scraper (Model #: 615C) must travel down a 3% slope on an unmaintained hard road (tire penetration is 5 inches and the coefficient of traction is estimated to be 0.45), and then return to the same location. Only the front tires of this scraper are powered, and you can obtain the following information from the manufacturer’s data. Empty vehicle weight: 97,000 lb; Fully loaded vehicle weight: 172,000 lb; When empty, 37% of the weight on the rear tires, 63% on the front tires; When fully loaded, 50% of the weight on the rear tires, 50% on the front tires;What is the total effective grade when hauling down the slope?

A contractor plans to excavate 3,900 bank cubic yards from a…

A contractor plans to excavate 3,900 bank cubic yards from a site. He needs to have 1,250 compacted cubic yards for the backfill of excavations. The soil test shows that the soil has a bank density of 1,800 pounds per cubic yard, a loose density of 1,500 pounds per cubic yard, and a compacted density of 2,400 pounds per cubic yard. He plans to use a truck that can haul 20 loose cubic yard per load. How many full truckloads of loose excess material should be hauled off the site?