A wheel-type tractor-scraper is operating on a 4% adverse grade. Assume that no power d...

A wheel-type tractor-scraper is operating on a 4% adverse grade. Assume that no power derating is required for equipment condition, altitude, and temperature. Use equipment data from Fig. 10.9. Disregarding traction limitations, what is the maximum value of rolling resistance (in lb per ton) over which the empty unit can maintain a speed of 14 mph?