Final answer:
In a theoretical scenario with no friction, a car that is started and moves would not require continuous pressing of the gas pedal to maintain constant speed according to Newton's first law. However, in the real world, friction and air resistance necessitate the application of force, by pressing the gas pedal, to keep the car at constant speed.
Step-by-step explanation:
If a car experiences no frictional force and is started and caused to move, for the car to continue in that motion, theoretically, the gas pedal would not have to be used continuously according to Newton's first law of motion. Once the car is set into motion and since it is mentioned there is no friction (a force that typically opposes motion), it would maintain a constant velocity without the need for additional force application. Thus, once the car is moving, you do not need to apply the gas pedal to keep it moving at constant velocity in an ideal, frictionless situation.
In reality, however, cars are not closed systems; energy is constantly added to the system (for example, fueling the tank) and lost due to factors like air resistance and friction. So when you drive in a real-world scenario with non-negligible friction, pushing down the gas pedal increases the flow of gasoline to the engine, which keeps the car moving at constant speed despite friction.