For a truck to maintain a constant speed on level ground, the engine must supply power to counteract the various forces opposing its motion. What are these resistances to forward motion?

Question

DentroTest · Accepted Answer

When a heavy vehicle travels at a constant speed on level ground, the power developed by the engine is used entirely to counteract three forces opposing forward motion: Aerodynamic drag: the force the air exerts against the passage of the vehicle, especially high in trucks because of their large frontal area and volume. Rolling resistance: caused by the continuous deformation of the tires as they contact the roadway and by the friction of the tread on the road surface. Transmission resistance: generated by the internal mechanical friction between the components of the drivetrain (gearbox gears, driveshaft, differential and axle shafts). The other options are incorrect because they use concepts that belong to aircraft aerodynamics (lift) or confuse individual components with the technical categories of the vehicle's dynamic resistance.

For a truck to maintain a constant speed on level ground, the engine must supply power to counteract the various forces opposing its motion. What are these resistances to forward motion?

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