What is acceleration?
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Joined: Oct 2003
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From: B.C. Canada
What is acceleration?
Stolen from Revscene.net
* One Top Fuel dragster 500 cubic inch Hemi engine makes more horsepower than the first 4 rows at the Daytona 500.
* Under full throttle, a dragster engine consumes 1½ gallons of nitromethane per second; a fully loaded 747 consumes jet fuel at the same rate with 25% less energy being produced.
* A stock Dodge Hemi V8 engine cannot produce enough power to drive the dragster supercharger.
* With 3000 CFM of air being rammed in by the supercharger on overdrive, the fuel mixture is compressed into a near-solid form before ignition. Cylinders run on the verge of hydraulic lock at full throttle.
* At the stoichiometric 1.7:1 air/fuel mixture for nitromethane the flame front temperature measures 7050 degrees F.
* Nitromethane burns yellow. The spectacular white flame seen above the stacks at night is raw burning hydrogen, dissociated from atmospheric water vapor by the searing exhaust gases.
* Dual magnetos supply 44 amps to each spark plug. This is the output of an arc welder in each cylinder.
* Spark plug electrodes are totally consumed during a pass. After 1/2 way, the engine is dieseling from compression plus the glow of exhaust valves at 1400 degrees F. The engine can only be shut down by cutting the fuel flow.
* If spark momentarily fails early in the run, unburned nitro builds up in the affected cylinders and then explodes with sufficient force to blow cylinder heads off the block in pieces or split the block in half.
* In order to exceed 300 mph in 4.5 seconds dragsters must accelerate at an average of over 4G's. In order to reach 200 mph well before half-track, the launch acceleration approaches 8G's .
* Dragsters reach over 300 miles per hour before you have completed reading this sentence.
* Top Fuel Engines turn approximately 540 revolutions from light to light!
* Including the burnout the engine must only survive 900 revolutions under load.
* The red-line is actually quite high at 9500 rpm.
* The Bottom Line; Assuming all the equipment is paid off, the crew worked for free, and for once NOTHING BLOWS UP, each run costs an estimated US $1,000.00 per second. The current Top Fuel dragster elapsed time record is 4.441 seconds for the quarter mile (10/05/03, Tony Schumacher). The top speed record is 333.00 mph (533 km/h) as measured over the last 66' of the run (09/28/03 Doug Kalitta).
Putting all of this into perspective:
You are driving the average $140,000 Lingenfelter "twin-turbo" powered Corvette Z06. Over a mile up the road, a Top Fuel dragster is staged and ready to launch down a quarter mile strip as you pass. You have the advantage of a flying start. You run the 'Vette hard up through the gears and blast across the starting line and past the dragster at an honest 200 mph. The 'tree' goes green for both of you at that moment. The dragster launches and starts after you. You keep your foot down hard, but you hear an incredibly brutal whine that sears your eardrums and within 3 seconds the dragster catches and passes you. He beats you to the finish line, a quarter mile away from where you just passed him.
Think about it, from a standing start, the dragster had spotted you 200 mph and not only caught, but nearly blasted you off the road when he passed you within a mere 1320 foot long race course.
That, folks, is acceleration
* One Top Fuel dragster 500 cubic inch Hemi engine makes more horsepower than the first 4 rows at the Daytona 500.
* Under full throttle, a dragster engine consumes 1½ gallons of nitromethane per second; a fully loaded 747 consumes jet fuel at the same rate with 25% less energy being produced.
* A stock Dodge Hemi V8 engine cannot produce enough power to drive the dragster supercharger.
* With 3000 CFM of air being rammed in by the supercharger on overdrive, the fuel mixture is compressed into a near-solid form before ignition. Cylinders run on the verge of hydraulic lock at full throttle.
* At the stoichiometric 1.7:1 air/fuel mixture for nitromethane the flame front temperature measures 7050 degrees F.
* Nitromethane burns yellow. The spectacular white flame seen above the stacks at night is raw burning hydrogen, dissociated from atmospheric water vapor by the searing exhaust gases.
* Dual magnetos supply 44 amps to each spark plug. This is the output of an arc welder in each cylinder.
* Spark plug electrodes are totally consumed during a pass. After 1/2 way, the engine is dieseling from compression plus the glow of exhaust valves at 1400 degrees F. The engine can only be shut down by cutting the fuel flow.
* If spark momentarily fails early in the run, unburned nitro builds up in the affected cylinders and then explodes with sufficient force to blow cylinder heads off the block in pieces or split the block in half.
* In order to exceed 300 mph in 4.5 seconds dragsters must accelerate at an average of over 4G's. In order to reach 200 mph well before half-track, the launch acceleration approaches 8G's .
* Dragsters reach over 300 miles per hour before you have completed reading this sentence.
* Top Fuel Engines turn approximately 540 revolutions from light to light!
* Including the burnout the engine must only survive 900 revolutions under load.
* The red-line is actually quite high at 9500 rpm.
* The Bottom Line; Assuming all the equipment is paid off, the crew worked for free, and for once NOTHING BLOWS UP, each run costs an estimated US $1,000.00 per second. The current Top Fuel dragster elapsed time record is 4.441 seconds for the quarter mile (10/05/03, Tony Schumacher). The top speed record is 333.00 mph (533 km/h) as measured over the last 66' of the run (09/28/03 Doug Kalitta).
Putting all of this into perspective:
You are driving the average $140,000 Lingenfelter "twin-turbo" powered Corvette Z06. Over a mile up the road, a Top Fuel dragster is staged and ready to launch down a quarter mile strip as you pass. You have the advantage of a flying start. You run the 'Vette hard up through the gears and blast across the starting line and past the dragster at an honest 200 mph. The 'tree' goes green for both of you at that moment. The dragster launches and starts after you. You keep your foot down hard, but you hear an incredibly brutal whine that sears your eardrums and within 3 seconds the dragster catches and passes you. He beats you to the finish line, a quarter mile away from where you just passed him.
Think about it, from a standing start, the dragster had spotted you 200 mph and not only caught, but nearly blasted you off the road when he passed you within a mere 1320 foot long race course.
That, folks, is acceleration
Senior Member
Joined: May 2000
Posts: 873
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From: Somewhere in the EU
What is acceleration?
Acceleration is one of those words for which we have a common meaning and a meaning that is specific to the field of physics. Ask the average person on the street and they will define acceleration as "speeding up." However, this is just a portion of the full meaning of acceleration as used in physics. In physics, acceleration is defined as a change in velocity. Considering this definition closely, we remember that velocity is defined as speed in a given direction. Therefore changing the velocity of an object means changing its speed (rate of motion), its direction of travel or both variables. An object experiencing a change of speed or direction is said to be accelerating.
Mathematically, we can express acceleration with the following formula:
a = (vf - vo)/t
where:
a - acceleration
vf - final velocity
vo - original velocity
t - time
The value for acceleration may be a negative or positive value depending on magnitude of vf and vo, but it is still properly termed acceleration (although we do often call negative acceleration "deceleration").
The unit for acceleration takes the form of
velocity/time2
where the time unit for velocity matches the time unit in the denominator of the acceleration formula. For example:
m/sec2
km/hr2
cm/min2
The derivation of this unit makes sense if it is broken down into simple steps:
Let's report our velocity measurements in m/sec and our time unit in seconds. When we solve the numerical portion of our equation we are left with:
m/sec
___________________
sec
Remembering back to basic math, when we divide a number by another, it is the same as multiplying by the inverse of the second number. For instance:
3/4 = 3 x 1/4
By the same principle:
m/sec/sec = m/sec x 1/sec
The resulting unit would therefore be m/sec2.
Acceleration is one of those words for which we have a common meaning and a meaning that is specific to the field of physics. Ask the average person on the street and they will define acceleration as "speeding up." However, this is just a portion of the full meaning of acceleration as used in physics. In physics, acceleration is defined as a change in velocity. Considering this definition closely, we remember that velocity is defined as speed in a given direction. Therefore changing the velocity of an object means changing its speed (rate of motion), its direction of travel or both variables. An object experiencing a change of speed or direction is said to be accelerating.
Mathematically, we can express acceleration with the following formula:
a = (vf - vo)/t
where:
a - acceleration
vf - final velocity
vo - original velocity
t - time
The value for acceleration may be a negative or positive value depending on magnitude of vf and vo, but it is still properly termed acceleration (although we do often call negative acceleration "deceleration").
The unit for acceleration takes the form of
velocity/time2
where the time unit for velocity matches the time unit in the denominator of the acceleration formula. For example:
m/sec2
km/hr2
cm/min2
The derivation of this unit makes sense if it is broken down into simple steps:
Let's report our velocity measurements in m/sec and our time unit in seconds. When we solve the numerical portion of our equation we are left with:
m/sec
___________________
sec
Remembering back to basic math, when we divide a number by another, it is the same as multiplying by the inverse of the second number. For instance:
3/4 = 3 x 1/4
By the same principle:
m/sec/sec = m/sec x 1/sec
The resulting unit would therefore be m/sec2.
Member
Joined: Oct 2000
Posts: 40
Likes: 0
From: Texas, USA
Originally posted by kobiashi
...
The unit for acceleration takes the form of
velocity/time2
where the time unit for velocity matches the time unit in the denominator of the acceleration formula. For example:
m/sec2
km/hr2
cm/min2
... [/B]
...
The unit for acceleration takes the form of
velocity/time2
where the time unit for velocity matches the time unit in the denominator of the acceleration formula. For example:
m/sec2
km/hr2
cm/min2
... [/B]
Seems to me the unit for acceleration is distance/time2, not velocity/time2.In your original equation you had acceleration equal to the difference in velocity divided by time. Velocity has units of distance divided by time, (which is the same as saying the difference of velocities has units of distance divided by time).
So, acceleration is distance divided by time divided by time again. Or distance divided by the product of time and time...Follow that?
If you are going to give us a boring lecture on physics, at least make it correct!
(just funnin' with ya...)
Senior Member
Joined: May 2000
Posts: 873
Likes: 1
From: Somewhere in the EU
I know nothing about physics...I just copied it off of some web site....
http://www.gmhsscience.com/problems/acceleration.htm
I had nothing better to do and thought I'd be a wise-***...
You're probably correct....
Carry on....
http://www.gmhsscience.com/problems/acceleration.htm
I had nothing better to do and thought I'd be a wise-***...
You're probably correct....
Carry on....
Senior Member
Joined: Sep 2003
Posts: 3,053
Likes: 0
From: Aggieland, TX
Acceleration is the change in velocity over time.
m/s^s is said "meters per second per second"
which means the change in velocity (meters per second), per second.
"acceleration is distance divided by time divided by time again."
Yes and no. You cant just take the distance and divide by time twice (I sure wish it worked that way).
There are actually 4 or 5 formulas for finding acceleration, velocity, time...
You could always do a google for "kinematics" if you really want :P
http://www.glenbrook.k12.il.us/gbssc...Kin/U1L6a.html
m/s^s is said "meters per second per second"
which means the change in velocity (meters per second), per second.
"acceleration is distance divided by time divided by time again."
Yes and no. You cant just take the distance and divide by time twice (I sure wish it worked that way).
There are actually 4 or 5 formulas for finding acceleration, velocity, time...
You could always do a google for "kinematics" if you really want :P
http://www.glenbrook.k12.il.us/gbssc...Kin/U1L6a.html
Last edited by Johngs; Nov 13, 2003 at 11:58 PM.
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Junior Member
Joined: Aug 2003
Posts: 0
Likes: 0
From: Lawrenceville, GA
Originally posted by TexasSteve
Seems to me the unit for acceleration is distance/time2, not velocity/time2.
In your original equation you had acceleration equal to the difference in velocity divided by time. Velocity has units of distance divided by time, (which is the same as saying the difference of velocities has units of distance divided by time).
So, acceleration is distance divided by time divided by time again. Or distance divided by the product of time and time...Follow that?
If you are going to give us a boring lecture on physics, at least make it correct!
(just funnin' with ya...)
Seems to me the unit for acceleration is distance/time2, not velocity/time2.
In your original equation you had acceleration equal to the difference in velocity divided by time. Velocity has units of distance divided by time, (which is the same as saying the difference of velocities has units of distance divided by time).
So, acceleration is distance divided by time divided by time again. Or distance divided by the product of time and time...Follow that?
If you are going to give us a boring lecture on physics, at least make it correct!
(just funnin' with ya...)
What you want to do is take the difference in your velocities and then divide that by time. As in:
a = (v1 - v2) / t
That's something you could use for dragsters since we're taking a straight line in one direction. Velocity is directional. Things get really interesting when we go into vectors (measurement of magnitude plus a direction, i.e. 70mph east). But that's more typing than I feel like doing while I'm at work...
Member
Joined: Oct 2000
Posts: 40
Likes: 0
From: Texas, USA
Originally posted by 36fan
Acceleration being a change in velocity over time (delta-V / t). You can't just take distance and divide it by time twice....
Acceleration being a change in velocity over time (delta-V / t). You can't just take distance and divide it by time twice....
Just like a velocity is the change in location over time, acceleration is the change in velocity over time. You no more divide a coordinate by time to get velocity than you divide a velocity by time to get acceleration. Rather, you take the change in coordinates and divide by time to get velocity, and you take the change in velocity and divide by time to get acceleration.
Probably we (me especially) need to get a life
