Determine The Power Required To Overcome Rolling Resistance For A Truck?

Question

A major force opposing the motion of a vehicle is the rolling resistance of the tires F(r), given by

F(r) = f ω

where f is a constant called the rolling resistance coefficient and ω is the vehicle weight. Determine the power, in kW, required to overcome rolling resistance for a truck weighing 322.5 kN that is moving at 110 km/h. Let f = 0.0069

So far I got:

F(r) = (0.0069) * ( 322.5)

F(r) = 2.22525

P = W / t ???

Answer 1

So far so good! Ok, so what's W? It's F*d, right? So you have:

P=F*d/t

and d/t is V, which in this problem is 110 km/h.

You have all that you want. Just convert km/h to m/s and substitute the values.