Originally Posted by Pharmacist (Post 247269)

Actually, the moon has no atmosphere, so the Z won't reach any speed in excess of 0, unless you modify it to accept oxygen from a solid state oxidizing agent

Originally Posted by speedoflife (Post 247270)

Physics FTW. Air resistance is a force. Any force that acts upon an object will cause it to accelerate. In this particular case, air resistance does actually slow the car down. The faster the car goes, the greater the force against the car. Without friction/air resistance/restrictive forces, anything with a force acting upon it will accelerate infinitely. [sigma]F=ma (net force=mass x acceleration) With one force and a constant mass, something would accelerate forever to an infinite speed.

Originally Posted by speedoflife (Post 247272)

Exactly. Arguments about a car on a moon are a wee bit ridiculous, but as are most tangents.

Originally Posted by Pharmacist (Post 247278)

Not to mention that the moon has a very rough bumpy surface, so even if you get the z to move, you will be leaving bits of undercarriage, exhaust, suspension, etc.... all over the place

Originally Posted by Pharmacist (Post 247278)

Not to mention that the moon has a very rough bumpy surface, so even if you get the z to move, you will be leaving bits of undercarriage, exhaust, suspension, etc.... all over the place

Originally Posted by kannibul (Post 247282)

seems like i recently saw a video like that...

Originally Posted by Pharmacist (Post 247277)

Actually technically that's old school newtonian physics. In modern physics, relativity applies. What you said is true at lower speeds. However, as speed approaches the speed of light, newtonian physics ceases to be accurate and relativistic physics takes over. The energy required to accelerate an object of mass to speeds approaching the speed of light approaches infinity. An object with mass can never achieve the speed of light. Only an object with zero mass (i.e. a photon) can travel at the speed of light. And so far, there is no evidence that any object regardless of mass can travel faster than the speed of light. So infinite speed is a theoretical impossibility, at least according to what scientists think.

Originally Posted by kannibul (Post 247267)

Wrong. Moon has no air to resist. Dyno has no wind resistance. On the moon, the car would go as fast as it can barring friction losses with the brakes, drivetrain, front wheels, bearings, etc (provided it could breathe), and rolling losses (ie, tires). On a dyno, it'd go nearly to the theoretical limit, the difference being the same as on the moon, except without the front brakes/wheels being factors. Of course, I'm discounting gravity effect and lack of air for the moon.


So, let my try again:

You're driving along at 75MPH, 0MPH headwind. Your car is using (example) 65HP to perform this work.

You're driving along at 75MPH, 20MPH headwind. Your car is using 65+N HP now, because there is more resistance.

(You can change these numbers to driving at 75, with a 75 mph tailwind vs 75 with a 0mph wind)


Same effect applies when attempting to determine the maximum speed fo the vehicle. The faster you go, the more resistance is applied to the front of the vehicle.

As you increase speed, you increase air resistance. Lower drag coefficient means the car slips/cuts through the air more instead of creating turbulence which distorts the air, making it more resistant.

Imagine a biplane wing on a F18. It wouldn't got as fast...ever, given all things being equal.

Originally Posted by G37Sam (Post 247677)

Wrong again, you're arguing a different point than I am

What I'm trying to say

If you're @ 4k rpm on 4th doing say 100mph, you will do that irrespective of any other forces, for the rear wheels to do 100mph, your engine has to be at 4k rpm if in 4th, it's how the car's gearing has been setup. Air resistance aka drag force only affects how much TQ you'll need to get there i.e how much time I'll take you to get there, but once you're there, you will be doing 100 @ 4k rpm.

Take it easy guys I only said on the moon because I wanted to use the 0 air resistance factor, of course the cars won't move there lol

Originally Posted by cjof2003 (Post 249436)

Originally Posted by G37Sam (Post 247677)

Wrong again, you're arguing a different point than I am

What I'm trying to say

If you're @ 4k rpm on 4th doing say 100mph, you will do that irrespective of any other forces, for the rear wheels to do 100mph, your engine has to be at 4k rpm if in 4th, it's how the car's gearing has been setup. Air resistance aka drag force only affects how much TQ you'll need to get there i.e how much time I'll take you to get there, but once you're there, you will be doing 100 @ 4k rpm.

Take it easy guys I only said on the moon because I wanted to use the 0 air resistance factor, of course the cars won't move there lol