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some math i thought might be interesting.

Posted: Fri May 01, 2009 11:32 am
by avansc
okay. so i was wondering about how many G's a top fuel dragster pulls down the strip.
ps: i might be wrong on these numbers. please dont yell, just correct.

so lets say that 'a' = the acceleration

integrate we get speed
ax

integrate again we get distance
1/2(a)x^2

so for all intense purposes 1/4 mile is 400 meters.

so

400 = 1/2(a)x^2

800/x^2 = a

x being the time it takes in seconds to complete the 400 meters.
a being the force experienced as a linear representation (note: i know the force is initially higher and tapers off, but lets just play along)

so

800/4.5^2 = 39.506172839506172839506172839506
39.506172839506172839506172839506 / 9.8 = 4.03 G's.

thats quiet alot.

ps: turns out they experience around 5 G at the start.

Re: some math i thought might be interesting.

Posted: Fri May 01, 2009 2:14 pm
by kostiak2
*yell*

Re: some math i thought might be interesting.

Posted: Fri May 01, 2009 2:29 pm
by MarauderIIC
Cool. See you did learn something in school ;)

Re: some math i thought might be interesting.

Posted: Sat May 02, 2009 11:21 pm
by M_D_K
Still in physics mode I see ;)

pretty damn cool BTW

Re: some math i thought might be interesting.

Posted: Sun May 03, 2009 12:36 am
by Spikey
I found this on a Star Trek vrs Star Wars site ;)

Acceleration and G-force Calculator
"This calculator will let you work out the acceleration and G force for an object
over a set distance and time."
http://www.angelfire.com/empire/blueyar ... html#accel

Distance: 0.4 km
Time: 4.567 s

...calculate...

Acceleration: 0.04 km/s/s
G-Force: 3.91 g
Max speed reached: 0.15 km/sec ( 540 km/h or 336 mph )

Close enough, maybe you have a faster car. Who knows what else this calculator might take in consideration.

I found the number 4.567 seconds from the thumbnail caption on the 2nd pic here: http://en.wikipedia.org/wiki/Top_fuel

EDIT
oh snap, just realized 4.567 seconds is probably from the 1,000 foot (304 m) race and not a 400m... oh well close enough lol

Re: some math i thought might be interesting.

Posted: Sun May 03, 2009 12:36 pm
by avansc
Spikey wrote:I found this on a Star Trek vrs Star Wars site ;)

Acceleration and G-force Calculator
"This calculator will let you work out the acceleration and G force for an object
over a set distance and time."
http://www.angelfire.com/empire/blueyar ... html#accel

Distance: 0.4 km
Time: 4.567 s

...calculate...

Acceleration: 0.04 km/s/s
G-Force: 3.91 g
Max speed reached: 0.15 km/sec ( 540 km/h or 336 mph )

Close enough, maybe you have a faster car. Who knows what else this calculator might take in consideration.

I found the number 4.567 seconds from the thumbnail caption on the 2nd pic here: http://en.wikipedia.org/wiki/Top_fuel

EDIT
oh snap, just realized 4.567 seconds is probably from the 1,000 foot (304 m) race and not a 400m... oh well close enough lol
if you feed that calculater the numbers i used. 400 meters and 4.5 second (NOT 4.567) you get an average of 4.027G which looks alot like an unrounded value of 4.03 G's what i originally got.

not that G is just a constant of acceleration. depending on height from the earth really. but lets say 9.8 for all intense purposes.
and well it should actually be small g. G is the gravitational constant 6.67300 × 10-11 m^3 kg^-1 s^-2

g=-(mG)/(g^2)r^ roughtly -9.8m.s^-1