A four-wheel tractor whose operating weight is 47,877 lb is pulled up a road whose slope is +3.5% at a uniform speed. If the average tension in the towing cable is 4,860lb, what is the rolling resistance of the road? Solution Weight of tractor = 47877 lb tension in cable = 4860 lb grade factor = 3.5% tension required to overcome rolling resistance = tension in cable - grade resistance =  4860 - 3.5% x 47877 = 4860 - 1676 = 3184 lb Hence, rolling resistance = 3184 lb .

1. A four-wheel tractor whose operating weight is 47,877 lb is pulled up a road whose slope is
+3.5% at a uniform speed. If the average tension in the towing cable is 4,860lb, what is the
rolling resistance of the road?
Solution
Weight of tractor = 47877 lb
tension in cable = 4860 lb
grade factor = 3.5%
tension required to overcome rolling resistance = tension in cable - grade resistance
=Â Â 4860 - 3.5% x 47877
= 4860 - 1676
= 3184 lb
Hence, rolling resistance = 3184 lb