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

From: Rosemary Hackney <ltcrose_at_meteoritecentral.com>
Date: Thu Apr 22 10:32:45 2004
Message-ID: <001501c400e5\$ecd7e860\$187dd6d1_at_default>

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hmmmm.. In a vacuum, Galileo proved that a feather and a rock fell at =
the same rate. 32 ft per second per second. ( gravity )=20

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,

Rosie
----- Original Message -----=20
From: MexicoDoug_at_aol.com=20
To: ROBERT.D.MATSON_at_saic.com=20
Cc: meteorite-list_at_meteoritecentral.com=20
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 =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 =
(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): 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 =20

En un mensaje con fecha 03/02/2004 7:26:12 PM Mexico Standard Time, =
ROBERT.D.MATSON_at_saic.com escribe:

Hi Doug,
=20
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).
=20
To do this experiment properly, then, they're going to need to drop =
an object
of the proper density. --Rob

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<DIV><FONT face=3DArial size=3D2>hmmmm.. In a vacuum, Galileo proved =
that a feather=20
and a rock fell at the same rate.&nbsp; 32 ft per second per second. ( =
gravity )=20
</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT>&nbsp;</DIV>
<DIV><FONT face=3DArial size=3D2>The difference outside of a vacuum =
depends on the=20
density of air i.e sea level.. or airplane altitude.. Air currents.. =
temperature=20
and shape of the item.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT>&nbsp;</DIV>
<DIV><FONT face=3DArial size=3D2>Terminal velocity for a skydiver =
in&nbsp;vertical=20
position is _at_ 180 mph. Tracking ( delta position) maybe @ =
200mph.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT>&nbsp;</DIV>
<DIV><FONT face=3DArial size=3D2>by the by.. My bro was a champion flour =
bomber from=20
his little Grummen.( Ruffles,</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>cuz she had ridges) :-).</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT>&nbsp;</DIV>
<DIV><FONT face=3DArial size=3D2>Rosie</FONT></DIV>
<BLOCKQUOTE=20
BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV style=3D"FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV=20
style=3D"BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: =
black"><B>From:</B>=20
<A title=3DMexicoDoug_at_aol.com=20
href=3D"mailto:MexicoDoug_at_aol.com">MexicoDoug@aol.com</A> </DIV>
<DIV style=3D"FONT: 10pt arial"><B>To:</B> <A =
title=3DROBERT.D.MATSON_at_saic.com=20
href=3D"mailto:ROBERT.D.MATSON_at_saic.com">ROBERT.D.MATSON@saic.com</A> =
</DIV>
<DIV style=3D"FONT: 10pt arial"><B>Cc:</B> <A=20
title=3Dmeteorite-list_at_meteoritecentral.com=20
=
href=3D"mailto:meteorite-list_at_meteoritecentral.com">meteorite-list@meteor=
itecentral.com</A>=20
</DIV>
<DIV style=3D"FONT: 10pt arial"><B>Sent:</B> Tuesday, March 02, 2004 =
9:50=20
PM</DIV>
<DIV style=3D"FONT: 10pt arial"><B>Subject:</B> Re: [meteorite-list] A =
"Strike"=20
with a spare ball</DIV>
<DIV><BR></DIV><FONT face=3Darial,helvetica><FONT lang=3D0 =
face=3DArial size=3D2=20
FAMILY=3D"SANSSERIF" PTSIZE=3D"10">Hola Rob,<BR><BR>You're right about =
the=20
terminal velocity of a chondrite, in the shape of a bowling ball being =
much=20
faster than a conventional bowling ball.&nbsp; This might still be a =
little=20
counter intuitive, but, here are some 9 inch diameter bowling ball =
terminal=20
velocities (there's a lot of algebra behind all the numbers that=20
follow):<BR><BR>Doug's really heavy 14 pounder (6.35 kg): 153 mph (69=20
m/s)<BR>Rob's super duper heavy 16 pounder (7.26 kg): 164 mph (73 =
m/s)<BR>A=20
bowling ball with a density of 2g/mL =3D 12.51 kg =3D 27.6 pounds: 215 =
mph (96=20
m/s)<BR>Typical chondrite ball&nbsp; _at_ 3.65 g/mL (50.3 pounds or 22.83 =
kg):=20
291 mph (130 m/s)<BR>Iron meteorite ball _at_ 8.0 g/mL (110.3 pounds or =
50.0=20
kg):&nbsp; 431 mph (192 m/s)<BR><BR>Shield shaped Iron (Cabin Creek =
AR): 300=20
mph (134 m/s)<BR>Oriented fat beer can shaped Iron at 50 kg (length =
=3D 3 times=20
diameter): 700 mph (312 m/s)<BR><BR>Cabin Creek shaped Chrondrite: 202 =
mph (90=20
m/s)<BR>Oriented fat beer can chrondrite as above: 473 mph (211 =
m/s)<BR><BR>So=20
for a bowling ball shape, it would actually take an iron to achieve =
the 140=20
m/s, an ordinary chondrite falls somewhat slower, in the shape of a =
bowling=20
ball.<BR><BR>Could an ordinary Doug's bowling ball fall at the rate of =
a=20
chondrite?&nbsp; Maybe, at the limits.&nbsp; We have focused more on =
mass for=20
the given cross sectional area.&nbsp; But to fall at the same terminal =
rate,=20
all that is required is the same ratio of sqrt(mass)/sqrt(X-area) or =
really=20
just mass divided by area being the same.&nbsp; So, if it is twice the =

density, it needs to be cut in half.&nbsp; Could an Iron fall at the =
same rate=20
of the ordinary bowling ball?&nbsp; Probably not, but for =
illustration, let's=20
consider Cabin Creek, which is quite close to the 50 kg - the same =
size as our=20
bowling ball - and a wonderful oriented shield shape I'd say around =
the=20
dimension ratio 33 X 33 X 10.&nbsp; That actually gives around double =
the=20
surface area as the spherical solid bowling ball shape, so it probably =
fell at=20
about "only" 300 mph (134 m/s), close to a bowling ball =
chondrite.&nbsp; In=20
the other hand a cylindrical shape (I arbitrarily set the length three =
times=20
the diameter.<BR><BR>Of course there are other considerations like the =

frictional ablation shaping, which is why cylinders turn into =
nosecones and=20
bullets, and it is no wonder that the Cabin Creek sample was know to =
be hot=20
upon fall.&nbsp; All the acceleration due to gravity holding back a 50 =
kg mass=20
of iron several hundred miles per hour is dissapated into heat.&nbsp;=20
Alternately nosecones are more likely to be cool and also with less=20
thumbprinting.<BR><BR>The table above summarizes all my calculations, =
maybe=20
there is an error, but I hope not.&nbsp; This should clear up free =
fall of=20
stones that lose their "cosmic velocity" as well as for bowling balls, =
and how=20
it fits in.&nbsp; A person typically free falls at 110 mph or so =
thought they=20
can double that by playing with orientation.&nbsp; Ha.&nbsp; The =
calculations=20
also showe this doubling effect for likely masses.&nbsp; Keep in mind =
non iron=20
meteorites are practically never going to stand the shear frictional =
forces of=20
shield shapes and "explode" into pieces.&nbsp; Also for fun, an =
oriented=20
bowling ball that fractures in exactly two hemispherical pieces =
traveling=20
terminally at 150 mph will leave the two fragments at a terminal rate =
of ...=20
106 mph a piece.&nbsp; That's probably why "explosions" seem to =
brighten=20
fireballs.&nbsp; Suddenly the greater surface area for the same total =
mass=20
steps up the overal frictional energy released and the meteors slow =
down from=20
an instantly greater potential.<BR><BR>I get into this stuff.&nbsp; =
That's why=20
I liked the bowling ball expt. which really sounds like an excuse for =
some=20
fun.<BR><BR>Saludos<BR>Doug Dawn<BR>Mexico&nbsp;&nbsp; =
<BR><BR><BR><BR>En un=20
mensaje con fecha 03/02/2004 7:26:12 PM Mexico Standard Time,=20
ROBERT.D.MATSON_at_saic.com escribe:<BR>
<BLOCKQUOTE=20
style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #0000ff 2px =
solid; MARGIN-RIGHT: 0px"=20
TYPE=3D"CITE"><BR></FONT><FONT lang=3D0 style=3D"BACKGROUND-COLOR: =
#ffffff"=20
face=3DArial color=3D#0000ff size=3D2 FAMILY=3D"SANSSERIF" =
PTSIZE=3D"10"=20
BACK=3D"#ffffff">Hi Doug,</FONT><FONT lang=3D0 =
style=3D"BACKGROUND-COLOR: #ffffff"=20
face=3DArial color=3D#000000 size=3D3 FAMILY=3D"SANSSERIF" =
PTSIZE=3D"12"=20
BACK=3D"#ffffff"><BR>&nbsp; <BR></FONT><FONT lang=3D0=20
style=3D"BACKGROUND-COLOR: #ffffff" face=3DArial color=3D#0000ff =
size=3D2=20
FAMILY=3D"SANSSERIF" PTSIZE=3D"10" BACK=3D"#ffffff">Good point on =
the density of a=20
bowling ball.&nbsp; Intuitively, I would have guessed</FONT><FONT =
lang=3D0=20
style=3D"BACKGROUND-COLOR: #ffffff" face=3DArial color=3D#000000 =
size=3D3=20
FAMILY=3D"SANSSERIF" PTSIZE=3D"12" BACK=3D"#ffffff"><BR></FONT><FONT =
lang=3D0=20
style=3D"BACKGROUND-COLOR: #ffffff" face=3DArial color=3D#0000ff =
size=3D2=20
FAMILY=3D"SANSSERIF" PTSIZE=3D"10" BACK=3D"#ffffff">the density was =
around 2=20
g/cm^3, when in fact it is barely above 1 g/cm^3 --</FONT><FONT =
lang=3D0=20
style=3D"BACKGROUND-COLOR: #ffffff" face=3DArial color=3D#000000 =
size=3D3=20
FAMILY=3D"SANSSERIF" PTSIZE=3D"12" BACK=3D"#ffffff"><BR></FONT><FONT =
lang=3D0=20
style=3D"BACKGROUND-COLOR: #ffffff" face=3DArial color=3D#0000ff =
size=3D2=20
FAMILY=3D"SANSSERIF" PTSIZE=3D"10" BACK=3D"#ffffff">about 1.15 for a =
16-lb ball=20
(the mass I was assuming).&nbsp; An ordinary chondrite</FONT><FONT =
lang=3D0=20
style=3D"BACKGROUND-COLOR: #ffffff" face=3DArial color=3D#000000 =
size=3D3=20
FAMILY=3D"SANSSERIF" PTSIZE=3D"12" BACK=3D"#ffffff"><BR></FONT><FONT =
lang=3D0=20
style=3D"BACKGROUND-COLOR: #ffffff" face=3DArial color=3D#0000ff =
size=3D2=20
FAMILY=3D"SANSSERIF" PTSIZE=3D"10" BACK=3D"#ffffff">of the same size =
would weigh=20
close to 50 lbs!&nbsp; So yes, air friction is going to</FONT><FONT =
lang=3D0=20
style=3D"BACKGROUND-COLOR: #ffffff" face=3DArial color=3D#000000 =
size=3D3=20
FAMILY=3D"SANSSERIF" PTSIZE=3D"12" BACK=3D"#ffffff"><BR></FONT><FONT =
lang=3D0=20
style=3D"BACKGROUND-COLOR: #ffffff" face=3DArial color=3D#0000ff =
size=3D2=20
FAMILY=3D"SANSSERIF" PTSIZE=3D"10" BACK=3D"#ffffff">be a serious =
factor, and a=20
bowling ball isn't going to have a chance of reaching</FONT><FONT =
lang=3D0=20
style=3D"BACKGROUND-COLOR: #ffffff" face=3DArial color=3D#000000 =
size=3D3=20
FAMILY=3D"SANSSERIF" PTSIZE=3D"12" BACK=3D"#ffffff"><BR></FONT><FONT =
lang=3D0=20
style=3D"BACKGROUND-COLOR: #ffffff" face=3DArial color=3D#0000ff =
size=3D2=20
FAMILY=3D"SANSSERIF" PTSIZE=3D"10" BACK=3D"#ffffff">the terminal =
velocity of a=20
chondrite (let alone that of an iron).</FONT><FONT lang=3D0=20
style=3D"BACKGROUND-COLOR: #ffffff" face=3DArial color=3D#000000 =
size=3D3=20
FAMILY=3D"SANSSERIF" PTSIZE=3D"12" BACK=3D"#ffffff"><BR>&nbsp; =
<BR></FONT><FONT=20
lang=3D0 style=3D"BACKGROUND-COLOR: #ffffff" face=3DArial =
color=3D#0000ff size=3D2=20
FAMILY=3D"SANSSERIF" PTSIZE=3D"10" BACK=3D"#ffffff">To do this =
experiment=20
properly, then, they're going to need to drop an object</FONT><FONT =
lang=3D0=20
style=3D"BACKGROUND-COLOR: #ffffff" face=3DArial color=3D#000000 =
size=3D3=20
FAMILY=3D"SANSSERIF" PTSIZE=3D"12" BACK=3D"#ffffff"><BR></FONT><FONT =
lang=3D0=20
style=3D"BACKGROUND-COLOR: #ffffff" face=3DArial color=3D#0000ff =
size=3D2=20
FAMILY=3D"SANSSERIF" PTSIZE=3D"10" BACK=3D"#ffffff">of the proper =
density.&nbsp;=20
--Rob</FONT><FONT lang=3D0 style=3D"BACKGROUND-COLOR: #ffffff" =
face=3DArial=20
color=3D#000000 size=3D3 FAMILY=3D"SANSSERIF" PTSIZE=3D"12"=20
BACK=3D"#ffffff"><BR></BLOCKQUOTE><BR></FONT><FONT lang=3D0=20
style=3D"BACKGROUND-COLOR: #ffffff" face=3DArial color=3D#000000 =
size=3D2=20
FAMILY=3D"SANSSERIF" PTSIZE=3D"10"=20
BACK=3D"#ffffff"><BR></BLOCKQUOTE></FONT></FONT></BODY></HTML>

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Received on Wed 03 Mar 2004 01:07:51 AM PST

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