Transcript Document

Announcements 10/03/11
 Check course calendar
– Find link to lesson(s) for the week
– Check out assignments
 Course Pack should be available before
Thursday at UBS.
– Spectral analysis (preparatory work + exercise)
– Print your own copies for color
 Will get “real” star finder on Tuesday (please
return card-stock ones to TA)
 Open House Jacobsen Observatory - Weds.
9 pm (7 pm is full) - if clear!
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Loose ends - Sky View Cafe
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Loose Ends - Quarks
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MATTER AND ENERGY
Learning goals
Distinguish among the following kinds of energy
kinetic
thermal
gravitational potential
electric potential
radiative
mass energy
Give examples of how energy is conserved.
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The Atom + isotopes & ions
An atom that has lost 1 or more electrons
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Nomenclature you need to know
Astronomers note how many electrons the atom has
lost through Roman numerals.
H I = neutral hydrogen
He II = singly ionized helium
Ca II = singly ionized calcium
Fe IV = iron atom has lost 3 electrons
Fe XII = iron atom has lost ___?___ electrons
___?___ = oxygen atom missing 2 electrons
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States of matter
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Video taken by satellite STEREO
http://en.wikipedia.org/wiki/File:Encke_tail_rip_off.ogg
PLASMA
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Energy
Kinetic vs Gravitational Potential
KE = ½
2
mv
GPE = mgh
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Energy
Thermal
Thermal energy is a measure of the average kinetic energy
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of a system of particles.
Energy
Radiative
Electric Potential
+
-
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Energy
Gravitational Potential
vs
Electric Potential
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Mass Energy
Fission
E = mc2
Sun’s Core
Fusion
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Newton’s Laws of motion + Gravity
Learning Goals
 Relate each of Newton’s laws of motion to
terrestrial and celestial events
 Demonstrate knowledge of how the force of
gravity depends on the masses of the objects
and the distance between them through
mathematical analysis.
 Explain what we mean by conservation of
angular momentum
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Newton’s 1st Law of Motion
 An object resists its change in state: an object at
rest stays at rest and an object in motion stays in
motion unless acted upon by an outside force.
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Terrestrial example
Celestial example
Relate each of Newton’s laws of motion to terrestrial and celestial events
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Newton’s 2nd Law: a = F/m
Terrestrial example
Celestial example
Relate each of Newton’s laws of motion to terrestrial and celestial events
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Newton’s 3rd law
For every action there is an equal and opposite reaction.
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Terrestrial example
Relate each of Newton’s laws of motion to terrestrial and celestial events
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How gravity “works”
m1m2
Fgravity  G 2
d
Mm
Fg  G 2
R
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Inertia as experienced by
a sperm whale and a
bowl of petunias
Mm
F 2
R
F Mm 1
M
a  2
 2
m
R m R
M
gG 2
R
weight  m g
Whale weighs a lot more!
Experiences a much greater
force of gravity. Why, then,
would the whale and bowl of
petunias fall at same
acceleration? (They also
have same velocity when
they hit, but NOT the same
kinetic energy.)
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Conservation of ANGULAR momentum
Explanation:
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