A four wheel truck or whose operating weight is 12000 kg is pulled along a road having a rising slope of 2% at a uniform speed. Assume grade resistance factor = 10 kg/tonne. The tension in the tow cable is 720 kg. The rolling resistance of the road will be
A. 20 kg/tonne
B. 30 kg/tonne
C. 40 kg/tonne
D. 50 kg/tonne
Answer: Option C

Soln. GR= 2%x 12000
= 240 kg
W= 12000/1000
= 12 tons
Trq = T - GR
= 720 - 240
= 480kg
R.R= Trq /W
=480/12
=40kg/ton
how to solve?
how to solve ????