seminarski rad

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seminarski rad

• metode i znacaj odredivanja gravitacione
  konstante
• big G

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tri fundamentalne univerzalne konstante u prirodi

• brzina svetlosti C
• plankova konstanta h
• gravitaciona konstanta G

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Gundlach said

• "That is a huge embarrassment for modern physics,
  where we think we know everything so well and
  other constants are defined to many, many
  digits.
• Ovo je velika neprijatnost za modernu fiziku,
  gde mislimo da znamo sve tako dobro i gde su
  druge konstante odredene sa mnogo, mnogo
  decimala.

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isaac newton1678
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lord henry cavendish
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henry cavendish1798G6.75x10-11Nm2/kg2The
torsion balance experiment of Henry Cavendish who
in 1797 was the first to experimentally measure
the gravitational constant G.
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prikaz laboratorijske vebe
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neki od razloga za pojavu sistematskih greaka

• promenljivost torzionog momenta
• pomeranje podloge (podrhtavanja zemlje)
• uticaj masa tela iz okruenja
• nehomogenost masa tela koja su sastavni deo
  eksperimenta
• gradijent gravitacionog polja
• gradijent temperature
• magnetni i elektricni uticaj

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skica eksperimenta torzionom vagom
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• G gravitaciona konstanta
• L rastojanje izmedu tela malih masa
• q ugao otklona
• k torziona konstanta

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princip slobodnog pada
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Schematic view of the mass arrangement. The
test masses are alternately connected to the
balance by means of the mass exchanger and
their weight difference is determined. The field
masses are moved between the two positions I and
II. The forces on the upper test mass due to the
Earth, the field masses and tidal forces are
plotted for the two field-mass positions on the
left and right of the figure.  
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The orbiting Lageos satellite monitors its
position relative to the Earth using reflected
laser light. From the measured gravitational
force between satellite and our planet, and
independently measuring G, one can calculate the
mass of the Earth.
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fabry-perot eksperiment
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The apparatus used by the research group at the
University of Washington, Seattle, to measure G
to record high precision. The device, about two
feet across, measures the attractiveness between
a hanging plate (hidden inside the cylinder) and
several spheres which rotate about the cylinder.
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tacnost sata je uslovljena konstantnom vrednocu
perioda oscilovanja torzionog klatna za dati
momenat inercije