Question

A major force opposing the motion of a vehicle is the rolling resistance of the tires, Fr, given by Fr f w where f is a constant called the rolling resistance coefficient and w 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 5 0.0069

Answer 1

`P = 68 kW`

Step-by-step explanation:

As we know that the friction force on the truck is given as

`f_f = f W`

here we know that

`W = 322.5 kN`

also we know that

`f = 0.0069`

so friction force on the truck is given as

`f_f = 0.0069 * 322.5 * 10^3`

`f_f = 2225.25 N`

Speed of the truck is given as

`v = 110 km/h`

`v = 30.56 m/s`

now the power is given as

`P = F.v`

`P = (2225.25)(30.56)`

`P = 68* 10^3 W`

`P = 68 kW`