Chronology Current Month Current Thread Current Date
[Year List] [Month List (current year)] [Date Index] [Thread Index] [Thread Prev] [Thread Next] [Date Prev] [Date Next]

Re: The Olympics



----- Original Message -----
From: "Herb Schulz" <herbs@INTERACCESS.COM>
To: <PHYS-L@lists.nau.edu>
Sent: Monday, September 25, 2000 12:28 PM
Subject: Re: The Olympics

1: What keeps the "gyros" pointing in the same direction?

The conservation of angular momentum.

The fact is that they are "disconnected" from the satellite itself so that
not external > torques can be applied to them and are used only to
measure a RELATIVE angular > position.

The fact is that your sentence is wrong in both syntax and physics. The
three gyros are each mounted in gimbal rings having three degrees of
freedom. When a torquing motor tries to rotate a gyro axis with respect to
the satellite frame, the result is that the satellite frame rotates with
respect to the gyro axis which continues to point to its reference star.

They really have nothing to do with changing the orientation of the
satellite.

Au contraire; they have everything to do with changing the orientation of
the satellite.

Aren't the "torquing motors" internal "objects" that are rotating against
the rest of the > satellite?

No. The motor frames are fixed with respect to the satellite frame. The
motor axes are fixed to the gimbal rings.

I see nothing in this comment that disagrees with what I said before.
maybe I'm missing > something.

My initial statement disagrees completely with what you said before. Please
read it again. It stands uncorrected.

"Is this a great country or what? It's the only country where the last two
words of the national anthem are Play Ball."

Paul O. Johnson
Collin County College