TECHNET Archives

October 2001

TechNet@IPC.ORG

Options: Use Monospaced Font
Show Text Part by Default
Show All Mail Headers

Message: [<< First] [< Prev] [Next >] [Last >>]
Topic: [<< First] [< Prev] [Next >] [Last >>]
Author: [<< First] [< Prev] [Next >] [Last >>]

Print Reply
Subject:
From:
"Bissonnette, Jean-Francois" <[log in to unmask]>
Reply To:
TechNet E-Mail Forum.
Date:
Thu, 11 Oct 2001 08:00:35 -0400
Content-Type:
text/plain
Parts/Attachments:
text/plain (154 lines)
We already said that the value of g is 9.81(m/s)/s.  That's an accelaration
value.  Say that an object falls for 10 sec before touching ground, then
it's speed will be (if we neglect air friction which in this case I think
would be neglectible anyway) 98.1 m/s.  If you consider the acceleration
formula which is  a= dv/dt ("d" standing for delta or variation)you'll get
an acceleration of -98.1(m/s)/s if you slow down your object in one second.
That is 10 times earth's g or 10G.

Now it's easy to get a much more important g force on an object.  Imagine
you let your coffee mug fall for one second, it will get to a speed of
9.81m/s.  If at the end of that second, concreet floor awaits, it will
only take a fraction of second before it's stoped, say 1/10 of a second
(probably conservative).  Then again your poor little mug will endure
10g's... and will be blown to bits!

-----Original Message-----
From: Brian Ellis [mailto:[log in to unmask]]
Sent: Thursday, October 11, 2001 2:08 AM
To: [log in to unmask]
Subject: Re: [TN] Question for the physics "gurus"


Ken

I'm damned sure that the black orange box may fall with an acceleration
of 1 g, up to when air resistance starts to slow it down, but if it
lands on a concrete road, it will decelerate at a very high value of g,
depending on the give in the concrete and the box itself. It's all a
matter of kinetic energy which is dissipated quasi-instantaneously. The
g-value would be lower if it landed on somebody's head, because the
latter being squashed down to the mid-torso would allow the acquired
energy from the free fall to be better dissipated. No mental energy
would be dissipated in such a case as the skull contents would be heated
to dissociation of the grey matter molecules into other carbon and
hydrogen combinations.

Brian

Ken Patel wrote:
>
> All,
> If G force is the gravitation force acting on the object then why many
times an object is
> being designed to take so may G forces. What I have heard that voice
recorder of the plane
> that went down in Pennsylvania can take on 700G force! So, if the free
fall is 1 G then why
> design 700 times safer. So, height above the ground does matter. May be I
got to take a look
> at the physic's book unless someone explain in layman's term.
>
> re,
> Ken Patel
>
> Timothy Reeves wrote:
>
> > No Jason,
> > I am not a guru, but that's OK. They are not interconvertible. One is a
> > measure of force, the other acceleration (actually a dimensionless
> > multiplier of the standard gravitational acceleration, g, 9.8 m/s^2). If
you
> > have an object in mind of a known mass, you could find the force exerted
on
> > it given the acceleration ("G's") by F = m a.
> >
> > Example: 100 gram object subjected to 5 G's ---------> F = 0.1 kg * 5 *
9.8
> > m/s^2 = 4.9 Newtons or 0.5 kilogram force or 1.1 lb-force.
> >
> > Tim Reeves
> >
> > -----Original Message-----
> > From: Jason Gregory [mailto:[log in to unmask]]
> > Sent: Tuesday, October 09, 2001 9:01 AM
> > Subject: Question for the physics "gurus"
> >
> > How do you convert pound/kilogram to G-force? Is this convertable? Since
> > G-force is somewhat time derived and pound/kilogram is force derived?
> > Any help is appreciated.
> >
> > Jason Gregory
> > Software Specialist - NPI Group
> > SCI Systems/Plant 2
> > 13000 S. Memorial Pkwy.
> > Huntsville, AL. 35803
> > (256) 882-4107 x3728
> > [log in to unmask]
> >
> >
----------------------------------------------------------------------------
-----
> > Technet Mail List provided as a free service by IPC using LISTSERV 1.8d
> > To unsubscribe, send a message to [log in to unmask] with following text
in
> > the BODY (NOT the subject field): SIGNOFF Technet
> > To temporarily halt delivery of Technet send the following message: SET
Technet NOMAIL
> > Search previous postings at: www.ipc.org > On-Line Resources & Databases
> E-mail Archives
> > Please visit IPC web site (http://www.ipc.org/html/forum.htm) for
additional
> > information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700
ext.5315
> >
----------------------------------------------------------------------------
-----
>
>
----------------------------------------------------------------------------
-----
> Technet Mail List provided as a free service by IPC using LISTSERV 1.8d
> To unsubscribe, send a message to [log in to unmask] with following text in
> the BODY (NOT the subject field): SIGNOFF Technet
> To temporarily halt delivery of Technet send the following message: SET
Technet NOMAIL
> Search previous postings at: www.ipc.org > On-Line Resources & Databases >
E-mail Archives
> Please visit IPC web site (http://www.ipc.org/html/forum.htm) for
additional
> information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700
ext.5315
>
----------------------------------------------------------------------------
-----

----------------------------------------------------------------------------
-----
Technet Mail List provided as a free service by IPC using LISTSERV 1.8d
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt delivery of Technet send the following message: SET
Technet NOMAIL
Search previous postings at: www.ipc.org > On-Line Resources & Databases >
E-mail Archives
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700
ext.5315
----------------------------------------------------------------------------
-----


WABTEC CORPORATION CONFIDENTIALITY NOTE
The content contained in this e-mail transmission is legally privileged and confidential information intended only for the use of the individual or entity named herein. If the reader of this transmission is not the intended recipient, you are hereby notified that any dissemination, distribution, or copying of this transmission is strictly prohibited.

---------------------------------------------------------------------------------
Technet Mail List provided as a free service by IPC using LISTSERV 1.8d
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt delivery of Technet send the following message: SET Technet NOMAIL
Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315
---------------------------------------------------------------------------------

ATOM RSS1 RSS2