Q: An engine provides 5.0 kN of force to keep a 1600-kg vehicle moving at a uniform speed. (Air resistance is negligible.) What is the coefficient of rolling friction between the tires and the road surface?
A: First convert 5.0 kN to Newtons: F = 5.0 kN = 5000 N. (Just like 5 kg = 5000 grams when measuring mass.)
You know it’s traveling at uniform speed, so this tells us that the right force = left force. There is no net force, because there is no acceleration!
F = 5000 N
m = 1600 kg
g = 9.8
Use this equation:
and solve for .