Louis,
the second law of Einstein is a thermodynamic occurance, does not imply on
the spinning of the PWB question. think you mean his THIRD law.It simply
says that each reaction is followed by counter reaction. "Newton's Third Law
of Motion. You've probably heard it before -- this law states that for every
action, there is an equal and opposite reaction. It simply means that for
every interaction between two objects, a pair of forces is working on both
of them. " When Pradeep's board starts spinning, it's exposed to an
acceleration, i.e. a force makes the PWB to move faster and faster. As long
as the input force is there, it goes on moving faster. It's accelerating.
When no further force is applied, there will be a equilibrium between the
input force (e.g.the spinning motor) and the counterforces (bearing
friction, air friction etc) and there is no longer an acceleration, BUT,
there is still a radial force, which is constant. Here comes the energy
into picture. It's the product of mass and velocity. And it increases with
the square of velocity. So, that's why I mentioned the starting condition of
Pradeep's monster apparatus. We have to condtions. The first is a dynamic
one and the other a static one. Now, someone else may explain in math terms,
I've forgotten most since decades. Maybe Brian, who is kind of universal
genious (extreme flattering) can give you a hand.
/Inge
----- Original Message -----
From: "Louis Hart" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Wednesday, December 16, 2009 8:41 PM
Subject: Re: [TN] Tensile strrength
Ahne, Technetters, keep in mind Newton's second law. If something is being
accelerated, it is experiencing a force. If it is not being accelerated,
there is no net force.
A force is required to keep an object moving in a circle, or ellipse (as the
Earth in its orbit), since the object's velocity is changing and it is
accelerating, constantly. After the part is ripped off, the only force it
experiences is that of gravity so it will be accelerated toward the center
of mass of the Earth.
A while back I read something by some philosopher, something like 'Newton's
theory of motion is the greatest intellectual achievement in human history'.
Einstein's General Theory of Relativity connecting gravitational mass with
the mass in Newton's second law must be way up on the list of intellectual
achievements, but I haven't gotten a good grasp of it. Any Technetters who
can help me understand it, please let me know offline.
Louis Hart
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Ahne Oosterhof
Sent: Wednesday, December 16, 2009 12:37 PM
To: [log in to unmask]
Subject: Re: [TN] Tensile strrength
And I expected to see "force", not "acceleration".
(The acceleration comes after the force has ripped the part off the board.)
Having fun,
Ahne
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Thayer, Wayne - IIW
Sent: Tuesday, 15 December, 2009 17:10
To: [log in to unmask]
Subject: Re: [TN] Tensile strrength
Just to add a number to this, I get over 9000G's of acceleration on the
parts near the ends of this board!
Wayne Thayer
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0
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 or (re-start) delivery of Technet send e-mail to
[log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to
[log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16
for additional information, or contact Keach Sasamori at [log in to unmask] or
847-615-7100 ext.2815
-----------------------------------------------------
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0
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 or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
-----------------------------------------------------
|
