On Wednesday, July 19, 2017 at 3:02:03 PM UTC-4, Mad Roger wrote:
On Wed, 19 Jul 2017 11:29:19 -0700 (PDT),
trader_4 wrote:

Look at the energy required to lift a 100 lb rock two feet. I can do
it two ways, with a 2ft lever that provides low torque, or a 10 ft
lever that applies higher torque. Which takes more *energy* to lift
the rock? Answer: they both take the same amount. Now apply that
to the fuel economy issue.

The problem is that the math is non linear.

The problem is that you don't understand the physics.



The physics forum said it this way.
https://www.physicsforums.com/thread...wheels.406860/

"attempting to spin a 2x larger wheel at the same speed would be attempting
to move the car 2x faster. Since energy is force x distance, traveling 2x
faster for 1 hour necessarily requires at least 2x more energy (since you
covered 2x more distance)...."

Or take the example of a bicycle with different gear ratios. While
the ratios vary, and with some ratios you couldn't get up a hill,
while with other ratios it's possible or even easy, it doesn't
change the energy input required.

The physics forum said otherwise.
https://www.physicsforums.com/thread...wheels.406860/

"Even more bad news is that in the real world, air resistance is actually a
square function! (2x more speed means 4x more air resistance!). This means
you would actually probably need at least 4x more energy..."

Now you're just deliberately throwing obfuscation into the problem.
Sure there is more wind resistance at higher speeds. But you were
talking about a car moving at the *same speed* down the highway
and saying that it involves more or less energy because of differing
torques. The bicycle example still applies. The bicycle moving at
the same speed will need the same *energy* input to get up a hill
but with different gear ratios, the torque applied at the peddles
will be different. You apply less torque over a greater peddle
movement distance or higher torque over a shorter distance, but
the energy input is the same. It's physics 101.