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[f1ea]

:hooli-popcorn:

I think I said continue to travel as oppsoed to continue to accelerate once the wheels lose contact with the ground.
EDIT:
or are you meaning that because a car that isn't in contact with the ground can't accelerate then it cannot be generating thrust?

I thought you were saying that the car could be generating thrust and accelerating just because it is producing Torque or HP (despite not being in contact with the ground) and that you can relate the car's HP/Torque output to the thrust it is generating. But reading back your posts, this is not what you are talking about.

[stonemonkey]

:hooli-popcorn:

I think I said continue to travel as oppsoed to continue to accelerate once the wheels lose contact with the ground.
EDIT:
or are you meaning that because a car that isn't in contact with the ground can't accelerate then it cannot be generating thrust?

I thought you were saying that the car could be generating thrust and accelerating just because it is producing Torque or HP (despite not being in contact with the ground) and that you can relate the car's HP/Torque output to the thrust it is generating. But reading back your posts, this is not what you are talking about.

What I am trying to say is that the car is using the earths mass as it's propellant and it is using the frictional force between the tyre rubber and the tarmac to apply the accelerating force (or that the frictional force is the accelerating force), accelerating the car in one direction and the earth (by a very small amount due to it's mass) in the other.

[Gaz]

Yeh that came out wrong, kinda ment it was being slowed down by it?

pushing against it that way.

Ah right, I see what you mean now, sorry.

Eitherway a car don't produce thrust right?

Do you agree or not with this:

When a car is sitting on an trolly and accelerates, the car will accelerate in one direction and the trolly it is sitting on will accelerate in the opposite direction

and, ignoring rolling and drag resistance

(mass of car*acceleration of car)=(mass of trolly*acceleration of trolly)

No because if it can move the trolly the car will push away from the trolly the trolly will move away from the car while the car will remain practicaly stationary as if its on a treadmill or rolling road.

[stonemonkey]

ok, you are now arguing with Sir Isaac Newton. Goodluck.

But tell me, what happens when you repeat the experiment with increasing mass of the trolly?

[Gaz]

ok, you are now arguing with Sir Isaac Newton. Goodluck.

But tell me, what happens when you repeat the experiment with increasing mass of the trolly?

Well thats just it you didn't specify he mass of the trolly.

i assumed it was light and the car just spins the trolly from underneath it

but if the trolly was heavy the car would just drive of the trolly.

i really dont' get your point eitherway?

What I am trying to say is that the car is using the earths mass as it's propellant and it is using the frictional force between the tyre rubber and the tarmac to apply the accelerating force (or that the frictional force is the accelerating force), accelerating the car in one direction and the earth (by a very small amount due to it's mass) in the other.

[/quote]

No the cars propellent is its fuel firing the cylinders in order to turn the axel with turns the wheels (which is torque) the wheels act as a fulcrum against the ground and it moves forward.

[stonemonkey]

You accepted earlier that throwing bricks out of a shopping trolly was in some wierd way a form of thrust, it's not wierd at all, it's exactly the same principle as how rockets work. In the case of most rockets the propellant is the energy source but not always, for example the ion rocket which uses electric charge to accelerate the propellant the fuel source being some type of electric cell and in the case of the shopping trolly, the brick is the propellant and the fuel source is the food you ate to give you the energy to throw it.

With the car sitting on a trolly, you accept that if the trolly has more mass than the car the car will accelerate more in one direction than the trolly will in the other and also that if the car has the greater mass then the trolly will accelerate more in one direction than the car will in the other direction. If they have equal mass then the acceleration of both will be equal but in opposite directions.
The force accelerating the trolly is the force that the tyres of the car exert on the trolly and the force accelerating the car is the force the trolly exerts on the tyres which is thrust, the mass of the trolly being the cars propellant which will be the case even if the trolly has the mass of a planet.

That is all accepted physics.

[stonemonkey]

Something that F1ea brought up, a car can't accelerate when it's in the air, that's the case no matter how much torque it puts into the wheels so how is the torque the accelerating force?

The car has to be on the ground so it has a mass to push against and two masses pushing against each other so they accelerate in opposite directions IS THRUST.

[bud]

my god we are talking about floating cars........

[stonemonkey]

my god we are talking about floating cars........

The wheels of a car can never leave the ground?



Can that car push against anything to accelerate by turning it's wheels?

[bud]

my god we are talking about floating cars........

The wheels of a car can never leave the ground?



Can that car accelerate by turning it's wheels?

the Torque WAS the accelerating force when it was on the ground you moron! or are you suggesting it just flew up there by some other means?

[stonemonkey]

my god we are talking about floating cars........

The wheels of a car can never leave the ground?



Can that car accelerate by turning it's wheels?

the Torque WAS the accelerating force when it was on the ground you moron! or are you suggesting it just flew up there by some other means?

There you go being abusive again.

If that's how you want to think the forces that make a car accelerate work, fine, carry on thinking like that.

[bud]

haha im fine mate you can have your floating cars....

[stonemonkey]

If anyone else is interested in finding out a bit more about this though, here's an article on it.

http://mb-soft.com/public2/car.html

[bud]

If anyone else is interested in finding out a bit more about this though, here's an article on it.

http://mb-soft.com/public2/car.html

all you need to read from this lecture is this quote

People generally talk about HORSEPOWER rather than Thrust with vehicles, but Thrust is generally described for aircraft and watercraft.

[f1ea]

There's no need to call anyone a moron. But anyway, like stonemonkey says, that flying car is no longer accelerating forward, despite the engine producing torque.

What i say about the earth's mass not being part of the car system is that its force can be considered infinite related to the friction able to be produced by the tires. So generally, you can 'cut' the system off at the friction force which is ussually available through empirical data (ie testing). This is why you see tire and track temp and tire wear is always measured.

In the case of a jet, the equivalent is air. A jet wouldnt be able to produce thrust without air, in fact the jet's thrust reduces as air density lessens (like the trolley example).

But the mass of air is being considered when you are calculating a jet's thrust; while the earth's mass isnt, when you are calculating a car's thrust... That's why i was disagreeing with stonemonkey, but what he is saying is right.