[meteorite-list] A "Strike" with a spare ball

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From: MexicoDoug_at_aol.com <MexicoDoug_at_meteoritecentral.com>
Date: Thu Apr 22 10:32:45 2004
Message-ID: <1e5.1a663ca0.2d77516a_at_aol.com>

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Hi Rosie - yes, though vacuums aren't widely availabe at sea level, nor do
objects accelerate at 32 f/s/s (9.8 m/s/s) until near sea level, try falling a
300 mph for a thrill (I believe it is down the road from you and they are still
signing competitive people up):
http://www.jumptown.com/events/speedskydiving.shtml
Saludos Doug

En un mensaje con fecha 03/03/2004 12:09:37 AM Mexico Standard Time,
ltcrose_at_bellsouth.net escribe:

> Asunto: Re: [meteorite-list] A "Strike" with a spare ball
> Fecha: 03/03/2004 12:09:37 AM Mexico Standard Time
> De: ltcrose_at_bellsouth.net
> Para: MexicoDoug_at_aol.com, ROBERT.D.MATSON@saic.com
> CC: meteorite-list_at_meteoritecentral.com
> Enviado por Internet
>
>
>
> hmmmm.. In a vacuum, Galileo proved that a feather and a rock fell at the
> same rate. 32 ft per second per second. ( gravity )
>
> The difference outside of a vacuum depends on the density of air i.e sea
> level.. or airplane altitude.. Air currents.. temperature and shape of the item.
>
> Terminal velocity for a skydiver in vertical position is _at_ 180 mph. Tracking
> ( delta position) maybe _at_ 200mph.
>
> by the by.. My bro was a champion flour bomber from his little Grummen.(
> Ruffles,
> cuz she had ridges) :-).
>
> Rosie
>
> >> ----- Original Message -----
>> From: MexicoDoug_at_aol.com
>> To: ROBERT.D.MATSON_at_saic.com
>> Cc: meteorite-list_at_meteoritecentral.com
>> Sent: Tuesday, March 02, 2004 9:50 PM
>> Subject: Re: [meteorite-list] A "Strike" with a spare ball
>>
>>
>> Hola Rob,
>>
>> You're right about the terminal velocity of a chondrite, in the shape of a
>> bowling ball being much faster than a conventional bowling ball. This might
>> still be a little counter intuitive, but, here are some 9 inch diameter
>> bowling ball terminal velocities (there's a lot of algebra behind all the
>> numbers that follow):
>>
>> Doug's really heavy 14 pounder (6.35 kg): 153 mph (69 m/s)
>> Rob's super duper heavy 16 pounder (7.26 kg): 164 mph (73 m/s)
>> A bowling ball with a density of 2g/mL = 12.51 kg = 27.6 pounds: 215 mph
>> (96 m/s)
>> Typical chondrite ball _at_ 3.65 g/mL (50.3 pounds or 22.83 kg): 291 mph (130
>> m/s)
>> Iron meteorite ball _at_ 8.0 g/mL (110.3 pounds or 50.0 kg): 431 mph (192
>> m/s)
>>
>> Shield shaped Iron (Cabin Creek AR): 300 mph (134 m/s)
>> Oriented fat beer can shaped Iron at 50 kg (length = 3 times diameter): 700
>> mph (312 m/s)
>>
>> Cabin Creek shaped Chrondrite: 202 mph (90 m/s)
>> Oriented fat beer can chrondrite as above: 473 mph (211 m/s)
>>
>> So for a bowling ball shape, it would actually take an iron to achieve the
>> 140 m/s, an ordinary chondrite falls somewhat slower, in the shape of a
>> bowling ball.
>>
>> Could an ordinary Doug's bowling ball fall at the rate of a chondrite?
>> Maybe, at the limits. We have focused more on mass for the given cross
>> sectional area. But to fall at the same terminal rate, all that is required is the
>> same ratio of sqrt(mass)/sqrt(X-area) or really just mass divided by area
>> being the same. So, if it is twice the density, it needs to be cut in half.
>> Could an Iron fall at the same rate of the ordinary bowling ball? Probably
>> not, but for illustration, let's consider Cabin Creek, which is quite close
>> to the 50 kg - the same size as our bowling ball - and a wonderful oriented
>> shield shape I'd say around the dimension ratio 33 X 33 X 10. That
>> actually gives around double the surface area as the spherical solid bowling ball
>> shape, so it probably fell at about "only" 300 mph (134 m/s), close to a
>> bowling ball chondrite. In the other hand a cylindrical shape (I arbitrarily
>> set the length three times the diameter.
>>
>> Of course there are other considerations like the frictional ablation
>> shaping, which is why cylinders turn into nosecones and bullets, and it is no
>> wonder that the Cabin Creek sample was know to be hot upon fall. All the
>> acceleration due to gravity holding back a 50 kg mass of iron several hundred
>> miles per hour is dissapated into heat. Alternately nosecones are more likely
>> to be cool and also with less thumbprinting.
>>
>> The table above summarizes all my calculations, maybe there is an error,
>> but I hope not. This should clear up free fall of stones that lose their
>> "cosmic velocity" as well as for bowling balls, and how it fits in. A person
>> typically free falls at 110 mph or so thought they can double that by playing
>> with orientation. Ha. The calculations also showe this doubling effect for
>> likely masses. Keep in mind non iron meteorites are practically never
>> going to stand the shear frictional forces of shield shapes and "explode" into
>> pieces. Also for fun, an oriented bowling ball that fractures in exactly two
>> hemispherical pieces traveling terminally at 150 mph will leave the two
>> fragments at a terminal rate of ... 106 mph a piece. That's probably why
>> "explosions" seem to brighten fireballs. Suddenly the greater surface area for
>> the same total mass steps up the overal frictional energy released and the
>> meteors slow down from an instantly greater potential.
>>
>> I get into this stuff. That's why I liked the bowling ball expt. which
>> really sounds like an excuse for some fun.
>>
>> Saludos
>> Doug Dawn
>> Mexico
>>
>>
>>
>> En un mensaje con fecha 03/02/2004 7:26:12 PM Mexico Standard Time,
>> ROBERT.D.MATSON_at_saic.com escribe:
>> >>>
>>> Hi Doug,
>>>
>>> Good point on the density of a bowling ball. Intuitively, I would have
>>> guessed
>>> the density was around 2 g/cm^3, when in fact it is barely above 1 g/cm^3
>>> --
>>> about 1.15 for a 16-lb ball (the mass I was assuming). An ordinary
>>> chondrite
>>> of the same size would weigh close to 50 lbs! So yes, air friction is
>>> going to
>>> be a serious factor, and a bowling ball isn't going to have a chance of
>>> reaching
>>> the terminal velocity of a chondrite (let alone that of an iron).
>>>
>>> To do this experiment properly, then, they're going to need to drop an
>>> object
>>> of the proper density. --Rob
>>>
>>
>

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<HTML><HTML>Hi Rosie - yes, though vacuums aren=
't widely availabe at sea level, nor do objects accelerate at 32 f/s/s (9.8=20=
m/s/s) until near sea level, try falling a 300 mph for a thrill (I believe i=
t is down the road from you and they are still signing competitive people up=
): 
<A HREF=3D"http://www.jumptown.com/events/speedskydiving.shtml">http://www.j=
umptown.com/events/speedskydiving.shtml</A> 
Saludos  Doug 
 
 
En un mensaje con fecha 03/03/2004 12:09:37 AM Mexico Standard Time, ltcrose=
_at_bellsouth.net escribe: 
 
<BLOCKQUOTE TYPE=3DCITE style=3D"BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT=
: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px">Asunto: Re: [meteorite-list]=
A "Strike" with a spare ball 
Fecha: 03/03/2004 12:09:37 AM Mexico Standard Time 
De: <A HREF=3D"mailto:ltcrose_at_bellsouth.net">ltcrose@bellsouth.net</A> 
Para: <A HREF=3D"mailto:MexicoDoug_at_aol.com">MexicoDoug@aol.com</A>, <A HREF=
=3D"mailto:ROBERT.D.MATSON_at_saic.com">ROBERT.D.MATSON@saic.com</A> 
CC: <A HREF=3D"mailto:meteorite-list_at_meteoritecentral.com">meteorite-list@m=
eteoritecentral.com</A> 
Enviado por Internet 
 
 
 
hmmmm.. In a vacuum, Galileo proved that a feather and a rock fell at the sa=
me rate.  32 ft per second per second. ( gravity ) 
 
The difference outside of a vacuum depends on the density of air i.e sea le=
vel.. or airplane altitude.. Air currents.. temperature and shape of the ite=
m. 
  
Terminal velocity for a skydiver in vertical position is _at_ 180 mph. Trackin=
g ( delta position) maybe _at_ 200mph. 
  
by the by.. My bro was a champion flour bomber from his little Grummen.( Ru=
ffles, 
cuz she had ridges) :-). 
  
Rosie 
 
<BLOCKQUOTE TYPE=3DCITE style=3D"BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT=
: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px">----- Original Message ----- <B=
R>
From: <A HREF=3D"mailto:MexicoDoug_at_aol.com">MexicoDoug@aol.com</A> <B=
R>
To: <A HREF=3D"mailto:ROBERT.D.MATSON_at_saic.com">ROBERT.D.MATSON@saic.=
com</A> 
Cc: <A HREF=3D"mailto:meteorite-list_at_meteoritecentral.com">meteorite-=
list_at_meteoritecentral.com</A> 
Sent: Tuesday, March 02, 2004 9:50 PM 
Subject: Re: [meteorite-list] A "Strike" with a spare ball 
 
 
Hola Rob, 
 
You're right about the terminal velocity of a chondrite, in the shape of a b=
owling ball being much faster than a conventional bowling ball.  This m=
ight still be a little counter intuitive, but, here are some 9 inch diameter=
bowling ball terminal velocities (there's a lot of algebra behind all the n=
umbers that follow): 
 
Doug's really heavy 14 pounder (6.35 kg): 153 mph (69 m/s) 
Rob's super duper heavy 16 pounder (7.26 kg): 164 mph (73 m/s) 
A bowling ball with a density of 2g/mL =3D 12.51 kg =3D 27.6 pounds: 215 mph=
(96 m/s) 
Typical chondrite ball  _at_ 3.65 g/mL (50.3 pounds or 22.83 kg): 291 mph=20=
(130 m/s) 
Iron meteorite ball _at_ 8.0 g/mL (110.3 pounds or 50.0 kg):  431 mph (192=
m/s) 
 
Shield shaped Iron (Cabin Creek AR): 300 mph (134 m/s) 
Oriented fat beer can shaped Iron at 50 kg (length =3D 3 times diameter): 70=
0 mph (312 m/s) 
 
Cabin Creek shaped Chrondrite: 202 mph (90 m/s) 
Oriented fat beer can chrondrite as above: 473 mph (211 m/s) 
 
So for a bowling ball shape, it would actually take an iron to achieve the 1=
40 m/s, an ordinary chondrite falls somewhat slower, in the shape of a bowli=
ng ball. 
 
Could an ordinary Doug's bowling ball fall at the rate of a chondrite? =
Maybe, at the limits.  We have focused more on mass for the given cros=
s sectional area.  But to fall at the same terminal rate, all that is r=
equired is the same ratio of sqrt(mass)/sqrt(X-area) or really just mass div=
ided by area being the same.  So, if it is twice the density, it needs=20=
to be cut in half.  Could an Iron fall at the same rate of the ordinary=
bowling ball?  Probably not, but for illustration, let's consider Cabi=
n Creek, which is quite close to the 50 kg - the same size as our bowling ba=
ll - and a wonderful oriented shield shape I'd say around the dimension rati=
o 33 X 33 X 10.  That actually gives around double the surface area as=20=
the spherical solid bowling ball shape, so it probably fell at about "only"=20=
300 mph (134 m/s), close to a bowling ball chondrite.  In the other han=
d a cylindrical shape (I arbitrarily set the length three times the diameter=
. 
 
Of course there are other considerations like the frictional ablation shapin=
g, which is why cylinders turn into nosecones and bullets, and it is no wond=
er that the Cabin Creek sample was know to be hot upon fall.  All the a=
cceleration due to gravity holding back a 50 kg mass of iron several hundred=
miles per hour is dissapated into heat.  Alternately nosecones are mor=
e likely to be cool and also with less thumbprinting. 
 
The table above summarizes all my calculations, maybe there is an error, but=
I hope not.  This should clear up free fall of stones that lose their=20=
"cosmic velocity" as well as for bowling balls, and how it fits in.  A=20=
person typically free falls at 110 mph or so thought they can double that by=
playing with orientation.  Ha.  The calculations also showe this=20=
doubling effect for likely masses.  Keep in mind non iron meteorites ar=
e practically never going to stand the shear frictional forces of shield sha=
pes and "explode" into pieces.  Also for fun, an oriented bowling ball=20=
that fractures in exactly two hemispherical pieces traveling terminally at 1=
50 mph will leave the two fragments at a terminal rate of ... 106 mph a piec=
e.  That's probably why "explosions" seem to brighten fireballs. =20=
Suddenly the greater surface area for the same total mass steps up the overa=
l frictional energy released and the meteors slow down from an instantly gre=
ater potential. 
 
I get into this stuff.  That's why I liked the bowling ball expt. which=
really sounds like an excuse for some fun. 
 
Saludos 
Doug Dawn 
Mexico   
 
 
 
En un mensaje con fecha 03/02/2004 7:26:12 PM Mexico Standard Time, ROBERT.D=
.MATSON_at_saic.com escribe: 
<BLOCKQUOTE TYPE=3DCITE style=3D"BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT=
: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px"> 
Hi Doug, 
 
Good point on the density of a bowling ball.  Intuitively, I would hav=
e guessed 
the density was around 2 g/cm^3, when in fact it is barely above 1 g/cm^3 -=
- 
about 1.15 for a 16-lb ball (the mass I was assuming).  An ordinary ch=
ondrite 
of the same size would weigh close to 50 lbs!  So yes, air friction is=
going to 
be a serious factor, and a bowling ball isn't going to have a chance of rea=
ching 
the terminal velocity of a chondrite (let alone that of an iron).<FO=
NT COLOR=3D"#000000" BACK=3D"#ffffff" style=3D"BACKGROUND-COLOR: #ffffff" S=
IZE=3D3 PTSIZE=3D12 FAMILY=3D"SANSSERIF" FACE=3D"Arial" LANG=3D"0"> 
 
To do this experiment properly, then, they're going to need to drop an obje=
ct 
of the proper density.  --Rob 
</BLOCKQUOTE> 
</BLOCKQUOTE> 
</BLOCKQUOTE> 
 
</HTML>
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Received on Wed 03 Mar 2004 10:19:06 AM PST

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