the basic question is:

if you are accelerating from a standing start, disregarding the launch aspect, full pelt in 1st and second, if you lift off, does the car still accelerate?

and, if so, why?

the reaso i ask is because i have had a bit of an arguement with someone and i reckon that you would still be under the influence of the momentumt/inertia/forward motion of accelerating to not stop accelrating the absolute instant you dipped the clutch

does this make any sense?

and where can i find some proper evidence of this other than my eyes on the speedo

 

you will still be accelerating as long as you engage clutch and lift of throttle at exactly the same time, if not you will be in engine braking once off throttle until the clutch is down. you defo are acelerating as ive looked at my speedo a few times when changing from 3rd to 4th and i engage clutch at 95 and its over 100 once im in 4th so im either still accelerating or my speedo cant keep up

 

The moment the clutch is disengaged the car will DECELERATE.

 

your rate of acceleration decreases but you still accellerate, but it gets slower and slower if you know what i mean... if you dipped your cluch and left it disengaged, you would slowly come to a standstill - i.e. decellerate...

 

V - U
---------
T



Once final velocity (or U) is reached then surely that's it, no more acceleration. As soon as you let off the max speed of that run or final velocity is reached so end of acceleration I'd say.

 

that shows your speed 'vs' time.

the diagonal lines show your increasing speed as you accellerate, and the slopes show the accelleration decreases, but your speed doesnt get less, just the rate of speed.... im trying to explain it here... but im not too sure if you will understand it... hope this helps though!

 

Rubbish!

If you dip the clutch your car will not accelerate!

 

You are totally and utterly mistaken.

Your speed will DROP when you disengage the clutch.

You will still cover distance, so maybe its distance not speed you are trying to talk about?????

 

no power,, no acceleration

 

if this is the case my speedo isnt keeping up with my acceleration then

 

So basically you're saying the car decelerates then

 

Not NO acceleration, LESS THAN NO acceleration, it will decelerate due to wind resistance and tyre losess etc.

 

it aint decellerating, the rate of accelleration is decreasing... likei said im not very good at explaining things...

 

of cause chip

 

My digital dash in my nova does that, I used to hit the rev limiter in 2nd on the nitrous about 5mph sooner than I hit it off the gas, just purely cause the speedo didnt poll often enough!

Same with a road angel etc

 

heres one,,,,
if you hit a fly when doing 100mph, does it make the car stop?

 

I understand fully what you are saying, its just that you happen to be totally and utterly completely wrong.

But you arent explaining it badly, PON misread what you said.

 

Took me a second to work that out as i was thinking that throwing something means no more power goes into it but it accelerates. Of course think about it for any longer than a second and you realise thats not true.

It will still be covering distance, perhaps at a decent rate, but it will bot increase in speed. As stated, it needs power to do that.

 

Depends on the weight of the car, the weight of the fly and the speed of the fly.

Generally though, no it doesnt.

 

they say there's no such thing as a stupid question, only stupid answers - but this thread proves otherwise

some people didn't pay any attention in physics lessons

 

if you were to accellerate strongly(foot to floor) to 100mph and at 100mph dip the clutch, then you would still accelerate for a few seconds, but it would not be as fast, so you would probably ony get to 103/104mph, after this you would decellerate due to friction and wird resistanc, but you would still be accellerating and the rate of accelleration would be less until you decellerate... its not an on/off switch... you can have periods of no accelleration and no decelleration...

 

NO YOU FUCKING WELL WOULDNT

PLEASE STOP BREATHING AIR THAT COULD BE USED BY SOMEONE USEFUL

 

www.migweb.co.uk

 

please would you explain it... im fairly sure i am right as you dont just start slowing down the second you dip the clutch, your accelleration decreases due to resistance, but your speed will not drop instantaniously... am i right??

 

Surely once the clutch has been dipped the engine isn't transmitting power hence the car entering coast down? It won't be say for arguments sake, sitting at 70 then go up to 72 with the clutch engaged? Any idiot knows thats wrong.

 

LOL

These lads could still teach them about 8 injector setups probably

 

i have to agree with chip i can not see how something can continue to accelerate. Maby you are thinking about going down a hill?

Also when you lift off the accelerator, there will still be fuel etc between the inlet and the pistons so maby that is the acceleration you are thinking about. or maby these cars that have electrics rather than cable for accel pedal. They may have a slight delay.

 

quality

 

so, let me try and get this:

you gun it in first
you change gear
you gun it in second
you dip the clutch

are you still accelerating when you change from first to second between the changes and when the clutch is disengaged for that fraction of a second?
ie, is your speed still increasing because the momentum of the vehicle is causing the car to accelerate, even for a split second, after you have stopped sending power throgh the transmission?

theory and practical seem to show 2 different things

the theory is that with no power you wouldn't accelerate any more, although you may be able to coast at that sort of speed for some distance before the speed starts to drop off
but the practical seems to be that the speedo tends to keep going after you've lifted, so does this mean the speedo needle is continuing to move after you've stopped accelerating?

i'm still confused

i can understand it the other way, as soon as you take your foot of the brake pedal, you don't slow down as quickly, but is it the opposite the other way around like it should be?

 

No, as soon as you disengage the clutch, your acceleration assumes a negative value and your speed begins to fall

momentum maintains speed, it does not raise it. All it affects is the rate of loos of speed due to resistive effects

The speedo is a big pile of wank and not to be believed, neither incidentally is gps, as it has a slo refresh rate and relies on doing the same thing for a period of time for accuracy.

Did no one else do o level physics?

 

F = MA

Therefore A = F/M


If you cant understand that, PLEASE stop commenting on this thread and giving DOJJ false hope he isnt totally wrong like always.

 

Just scanned thru not reading properly

But did anyone mention the ground you on

ie if you was travelling down hill you could keep accellerating but if you was going uphill you would start decellerating, if on a level ground then you would be slowing, slowly but slowing wether foot on or off clutch, with foot on you would be naturaly decellerating, with foot off you would actually be braking.

my view anyway lol

Steve

 

Don't think about speed, but momentum. If you think that the fly is travelling one direction, at speed X, then hits the car, and is if then going the opposite way at speed Y, then yes, it implies at some point that the flies velocity must equal zero, and as it is in contact with the car, the car must also stop.

BUT, if you consider momentum, all you do is sum the momentum of the two objects, so;

MassCar x VelocityCar - MassFly x VelocityFly = post impact momentum.

Then divide the new momentum by the mass of the car, and you see how much the car actually slowed down.

Mart

 

No power to the wheels your not going to Accelerate

 

Chip - I must have misread it, as I understand the concept fully.

If he is right though, he's invented a new form of propulsion, so should be applauded!

 

so it's basicly the speedo speeding up even though the vehciel ins't that gives the illusion that you are accelerating when you lift off/dip the clutch yes?

no?

something like that?

 

i think we are arguing the same point... i agree that if you were to keep your clutch dipped then you would decellerate, but for the small ammount of time while changing gear you would not notice it, but rather your accelleration decrease.

from what i was taught if you throw a ball, the second the ball leaves your thrust, theoretically there it should decellerate, but in reality there is a fraction of a second where the friction has not overcome the accelleration proficiently enough to affect the speed in a negative effect, so essentially it is still accellerating...

 

if you are, then youre making a crap job of it!!

yes, the speedo overruns as it has a time delay

 

if you throw a ball up as soon as it leaves your hand it is decelerating instantly, without any force how could it accelerate, they only acceleration acting on it will be mg (gravity) in the opposite direction.

basically with no force applied an object cannot accelerate.