posted by Kourt .
A car travels at a speed of 25 m/s on a flat stretch of road. The driver must maitain pressure on the accelerator to keep the car moving at a constant speed.
Are there any forces doing work on the car? Explain.
What is the net force?
The net force is zero.
The engine does work on the car, by applying a torque to the drive shaft. The work is necessary to overcome aerodynamic and internal (engine and bearing) friction.
The road applies a force to the tires to keep the car moving forward, but the road does not do work. The work is generated internally by the engine.