"Travis Marlatte" wrote:

Accelerating the mass to the same velocity requires the same energy
regardless of what the surface is doing but wheel drag cannot be totally
ignored.

True. Another factor that I ignored as being insignificant (and this
applies to the plane or car) is the extra energy it takes to provide
the angular acceleration of the wheel to higher rotational velocities.
E.g, at speed, one car includes 4 flywheels spinning with rim
velocities of 60mph, while the other car has 4 flywheels spinning with
rim velocities of 120mph. This additional energy need will cause
slower acceleration if the same power is available.

Why did you suggest that the car is providing the energy for the conveyor?
We've had one recent poster who apparently thought that the power
source for moving the conveyer was key to the problem. I'm not
suggesting THAT the car was providing the energy, but only examining
what IF it did.

This would imply wheels with normal friction behavior but a frictionless
conveyor with a brake.
Not needed. As long as the conveyer has less friction and mass than
the car, and has a brake to control its speed, the car can power it.
And how much power that absorbs will determine how much the car's
acceleration is lowed down. At the limit, it is CJ's speculation of
the car's acceleration to 120 (on the speedometer) matching a regular
road acceleration to 120.

A conveyor that is motor driven but controlled makes a more consistent
model.
Agreed.

I agree that very little additional thrust is necessary (either from the
wheels of a car or from the propeller of a plane) to counteract the
counter-moving conveyor. But some additional energy will be needed due to
the additional drag provided by the faster spinning wheels (both for the car
and the plane).
And to accelerate the wheels to a higher angular velocity, assuming
they are not massless.
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