I think the veyron's a very good looking beast
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I think the veyron's a very good looking beast
I know what you mean, it "feels" like it should be more like this:
(excuse the dodgy photochop)
http://www.stoo.org.uk/FighterT-A-chopped.jpg
Much slinkier!
Original for comparison:
http://www.bristolcars.co.uk/pics/FighterT-A.jpg
The chopped roof looks cool, dont think it'd fit in though. :P
Ugh typos got me again. Why am I still hungover at nearly 3pm :(
Lets try again...
The chopped roof looks cool, don't think I'd fit in though.
Blimey! ;)
Shorter legs, or sit in the back? :D
Meant to reply to this earlier, never got round to it. Thought I might as well do it now in the light of the interminable "plane on a treadmill" thread, which I read up until the point Nicho saw the light, and then gave up on;).
Power is proportional to force x velocity as you say- and consequently as a car accelerates, the accelerative force the engine is able to exert upon it decreases. In the hypothetical example of putting a rocket in deep space and then firing off the engines, the astronauts would experiece hard acceleration to start with which would gradually diminish as their speed increased. Kinetic energy is mass times velocity squared- which all matches up neatly, although I found it a bit counter-intuitive when I started A-Level physics.
In this instance (I.E. top speed of a car) we are talking about the power of the engine versus the frictional resistance of the wind, which increases with the square of the speed (as does, AFAIK, the mechanical resistance via the tyres and bearings, which in any case is far less important). Consequently to double your speed you need four times the power. I fail to see where any calculation involving the cube of the speed comes in?:confused:
Wind resistance increases as the square of the speed, correct.
The result of that is the force (not power) to overcome that resistance is squared. Bare in mind you are travelling at twice the speed, and at twice the speed to generate the same force, you need twice the power - as in power=force times velocity.
so you have power is proportional by the speed squared and multiplied by the top speed again - i.e. the top speed cubed.
power=force times velocity.
p=fv
force of resistance~velocity^2
f~V^2
substitute f in the top equation with v^2 and you get p~v^2v
p~v^3
Where ~ means proportional to.
Oh hellfire= I've just spent literally over any hour trying to pick your equations apart- in an alcohol befuddled state- before realising that my previous post was wrong. Power must equal force x velocity x mass- otherwise the weight of the object would have no bearing on its acceleration. Obviously, it does.
Anyway, terminal velocity of any object (in our earthbound frame of reference), be it a car with the throttle pinned, or a skydiver jumping out of a plane with only gravity accelerating them, occurs when the accelerative force reaches equilibrium with the decelerative force due to air resistance.
Air resistance (and AFAIK rolling resistance from the tyres etc.) is proportional to the square of the speed. If you have a car whose air and rolling resistance increases with the square of its speed (which is more or less any car), then if you quadruple the power you double the terminal velocity. The mass of the car only affects the time it will take to reach terminal velocity, as the engine has to impart more kinetic energy to it to accelerate it.
If that doesn't convince you, I'll bust out the equations tomorrow;),
power=force x velocity
There's no acceleration in there.
acceleration= force/mass
However at top speed no acceleration is occuring so it doesn't matter.
YepQuote:
Anyway, terminal velocity of any object (in our earthbound frame of reference), be it a car with the throttle pinned, or a skydiver jumping out of a plane with only gravity accelerating them, occurs when the accelerative force reaches equilibrium with the decelerative force due to air resistance.
Substitute the power in bold there with force. That is where you have gone wrong.Quote:
Air resistance (and AFAIK rolling resistance from the tyres etc.) is proportional to the square of the speed. If you have a car whose air and rolling resistance increases with the square of its speed (which is more or less any car), then if you quadruple the power you double the terminal velocity. The mass of the car only affects the time it will take to reach terminal velocity, as the engine has to impart more kinetic energy to it to accelerate it.
If that doesn't convince you, I'll bust out the equations tomorrow;),
To generate the same force at double the speed requires double the power.