Example problem and solution - Cstm 456

Example problem and solution - Cstm 456 - Example problem -...

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Example problem - Rolling Resistance 1. A large off road truck Cat 771D with a total GVW of 156,295 lbs. is traveling over a flat poorly maintained haul road which has a rolling resistance factor for the road surface of 120lb. /ton. What is the total resistance in pounds acting on the truck? TR = GR + RR GR = Truck weight in tons x grade 156,295 l b/ 2,000lb/ton = 78.25 GR TR = (78.25ton x 0x 20lb/ton) + 78.25ton x 120 lb/ton TR = 9,377.7 lb The 9,390 lb is the rimpull needed to maintain the trucks speed traveling over this road surface 2. What is the effective grade of the road surface only in the above problem? Because the road is flat there is no grade. The surface of the road has a rr = 120 lb/ton or an effective grade of 6% . 120 lb/ton / 20lb/ton = 6% Let’s check it out: .06 x 156,295lb = 9,377 You see, effective grade is the same as the rr of the road surface expressed in % 3. In the above problem number 1, using the same truck, same load, same road
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Example problem and solution - Cstm 456 - Example problem -...

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