FORUMula1.com - F1 Forum

[stonemonkey]

The mass being forced in the opposite direction is the trollys mass, It doesn't matter if the mass is solid,liquid or gas or comes from within the vehicle or not, a jet engine sucks in air and acceleratess it out the back at a high velocity .The force exerted between the tyres and the trolly force the trolly to accelerate in one direction and the car to accelerate in the opposite direction, they push each other in opposite directions. In the case of a car on the ground it's the earths mass but as f1ea said, the eaths mass is so big compared to the mass of a car that there will be very little effect on it and is usually ignored.

The Earth is not being expelled or accelerated.

its just stationary.

the earth is not stationary

LoL Yes but last time i checked when i did a fast start in my focus the earth didn't start spinning the other way.

So its stationary relative to the car.

For a rocket, the acceleration of the rocket can be found by:

Acceleration of rocket=(acceleration of propellant * mass of propellant) / mass of rocket

Similarly, (the earth can be considered the propelling mass of the car or the other way round btw)

Acceleration of earth=(acceleration of car * mass of car) / mass of earth

That's what it would be if the forces went through the centers of gravity of the car and the earth (which isn't really the case) but it'll give you a rough idea of the values involved if you care to work it out.

[f1ea]

LoL Yes but last time i checked when i did a fast start in my focus the earth didn't start spinning the other way.
So its stationary relative to the car.

Again, that's because the earth's mass is much larger than the car's. But it is NOT absolutely stationary, there is a tiny acceleration that is ultimately overwhelmed by gravitational forces (the sun, the moon whatever...); meaning no matter how many cars do a burnout at the same time, the forces they generate will never be comparable to the gravitational forces between the sun and the earth.

stone monkey, thrust for a glider?

A glider has potential energy from being at a higher position than it's destination.... but somebody had to spend energy to bring it up there. A glider will never end up higher than from where it initially set off from.

[stonemonkey]

A glider will never end up higher than from where it initially set off from.

Except when they use the thermal currents, in which case a glider could be considered to be solar powered.

But if the glider doesn't use the thermal currents to increase it's potential energy then what f1ea said is right, and for exactly the same reason that no hill on a roller coaster can be as high as the first.

[Gaz]

The mass being forced in the opposite direction is the trollys mass, It doesn't matter if the mass is solid,liquid or gas or comes from within the vehicle or not, a jet engine sucks in air and acceleratess it out the back at a high velocity .The force exerted between the tyres and the trolly force the trolly to accelerate in one direction and the car to accelerate in the opposite direction, they push each other in opposite directions. In the case of a car on the ground it's the earths mass but as f1ea said, the eaths mass is so big compared to the mass of a car that there will be very little effect on it and is usually ignored.

The Earth is not being expelled or accelerated.

its just stationary.

the earth is not stationary

LoL Yes but last time i checked when i did a fast start in my focus the earth didn't start spinning the other way.

So its stationary relative to the car.

For a rocket, the acceleration of the rocket can be found by:

Acceleration of rocket=(acceleration of propellant * mass of propellant) / mass of rocket

Similarly, (the earth can be considered the propelling mass of the car or the other way round btw)

Acceleration of earth=(acceleration of car * mass of car) / mass of earth

That's what it would be if the forces went through the centers of gravity of the car and the earth (which isn't really the case) but it'll give you a rough idea of the values involved if you care to work it out.

The earth has nothing to do with the car moving forward its just pulling the car down using gravity allowing the cars wheels to make contact and turn against it using Friction.

No thrust invloved

Again, that's because the earth's mass is much larger than the car's. But it is NOT absolutely stationary, there is a tiny acceleration that is ultimately overwhelmed by gravitational forces (the sun, the moon whatever...); meaning no matter how many cars do a burnout at the same time, the forces they generate will never be comparable to the gravitational forces between the sun and the earth.

Yeh i know i was being sarcastic, the earth don't move.

At all.

[stonemonkey]

I take it you've never studied physics Longbow?

[Gilles 27]

[stonemonkey]

Another forum with pretty much the same topic, read the first paragraph of the 2nd last post.

http://www.physicsforums.com/archive/in ... 24508.html

[f1ea]

Yeh i know i was being sarcastic, the earth don't move.
At all.

Oh I know it dont move. Its also flat.

[Gaz]

Another forum with pretty much the same topic, read the first paragraph of the 2nd last post.

http://www.physicsforums.com/archive/in ... 24508.html

Your car tires push on the ground with a force F and the ground pushes on the tires with an equal and opposite force F. Newtons third law, to every action there is an equal and opposite reaction.

Right? know that no mention of thrust there?

have you studyed physics or what?

[stonemonkey]

have you studyed physics or what?

A bit, yes. You?

You missed out something from that last link I gave.

And here's another link.

http://www.mansfieldct.org/schools/MMS/ ... npairs.htm

[Gaz]

have you studyed physics or what?

A bit, yes. You?

You missed out something from that last link I gave.

And here's another link.

http://www.mansfieldct.org/schools/MMS/ ... npairs.htm

Thrust of an F1 car then?

good luck working out that.

thats just using the term thrust in place of acceleration.

its not thrust wrong use of the word

[f1ea]

Thrust of an F1 car then?
good luck working out that.

THRUST = TORQUE x WHEEL RADIUS
(assuming the tire is not slipping)

BUT because car tires are likely to slip, car people dont use thrust to measure its abilty to accelerate. In fact, a car with too much thurst may not even be able to accelerate at all. Enter the transmission, torque curves, tire technology etc.
And when car people want to increase the ammount of maximum friction (ie thrust available) then enter aerodynamics.

Jet people do use thrust because, in practical terms, most jets will fly in the same air. So the same jet with a thrustier engine will accelerate more.

[stonemonkey]

THRUST = TORQUE x WHEEL RADIUS
(assuming the tire is not slipping)

Up to around 80mph the engine can generate more torque than is required to spin the wheels so for that speed range the max thrust is the potential tractive force of the tyre which increases with speed. Above 80mph when the downforce has more effect then THRUST = TORQUE x WHEEL RADIUS becomes the max thrust but that decreases as the car goes through the gears, So the max thrust an F1 car would generate would be at around that speed, worked out from either the potential tractive force or from the torque that can be delivered to the wheels through the transmission as both should be about equal at that point.

a car with too much thurst may not even be able to accelerate at all

Sure you don't mean torque? as too much torque means the tyres slip and you get reduced thrust.

[f1ea]

Sure you don't mean torque? as too much torque means the tyres slip and you get reduced thrust.

oops.
Yeah, too much torque and you may have no thrust at all. Thats why the transmission, aerodynamics, tire tech and the driver's ability is there: to maximise thrust.

Up to around 80mph the engine can generate more torque than is required to spin the wheels so for that speed range the max thrust is the potential tractive force of the tyre which increases with speed. Above 80mph when the downforce has more effect then THRUST = TORQUE x WHEEL RADIUS becomes the max thrust but that decreases as the car goes through the gears, So the max thrust an F1 car would generate would be at around that speed, worked out from either the potential tractive force or from the torque that can be delivered to the wheels through the transmission as both should be about equal at that point.

case solved

[stonemonkey]

I'm just looking around to see if I can find some info and allegedly the 2006 renault could go from 0-100km/h in 1.7 secs

That's averaging 16.3m/s/s

and to accelerate 605Kg at that rate using F=MA

F= 16.3 * 605 = 9,886N

but that's the average over that speed range and it's not including the force to overcome rolling resistance or drag

EDIT: oops, fixed calcs!