seminarskiseminarski rad rad

metode i značaj metode i značaj određivanja određivanja gravitacione gravitacione konstantekonstante

““big Gbig G””

tri tri fundamentalne univerzalne fundamentalne univerzalne konstante u prirodikonstante u prirodi

brzina svetlosti Cbrzina svetlosti Cplankova konstanta hplankova konstanta h

gravitaciona konstanta Ggravitaciona konstanta G

Gundlach saidGundlach said::

"That is a huge embarrassment for "That is a huge embarrassment for modern physics, where we think we modern physics, where we think we know everything so well and other know everything so well and other constants are defined to many, many constants are defined to many, many digitsdigits..““

““Ovo je velika neprijatnostOvo je velika neprijatnost za modernu za modernu fiziku, gde mislimo da znamo sve tako fiziku, gde mislimo da znamo sve tako dobro dobro i i gde su druge konstante gde su druge konstante određene sa mnogo, mnogo decimala.određene sa mnogo, mnogo decimala.””

iisaac newtonsaac newton16781678

2r

MmGF

lord hlord henryenry cavendishcavendish

henry cavendishhenry cavendish17981798

G=6.75x10G=6.75x10-11-11NmNm22/kg/kg22

The torsion balance experiment of Henry Cavendish who in 1797 was the first to The torsion balance experiment of Henry Cavendish who in 1797 was the first to experimentally measure the gravitational constant G. experimentally measure the gravitational constant G.

prprikaz laboratorijske vežbe ikaz laboratorijske vežbe

neki od razloga za pojavu neki od razloga za pojavu sistematskih gresistematskih grešakašaka

promenljivost torzionog momentapromenljivost torzionog momentapomeranje podloge (podrhtavanja pomeranje podloge (podrhtavanja

zemlje)zemlje)uticaj masa tela iz okruženjauticaj masa tela iz okruženjanehomogenost masa tela koja su nehomogenost masa tela koja su

sastavni deo eksperimentasastavni deo eksperimentagradijent gravitacionog poljagradijent gravitacionog poljagradijent temperaturegradijent temperaturemagnetni i električni uticajmagnetni i električni uticaj

skica eksperimenta torzionom skica eksperimenta torzionom vagomvagom

trr sin0

kF

k

IT 2

k

2/LF

2r

mMGF

mML

rkG

2

mML

rkG

2

G G gravitaciona konstantagravitaciona konstantaL L rastojanje između tela malih masarastojanje između tela malih masaugao otklonaugao otklonak k torziona konstantatorziona konstanta

princip slobodnog padaprincip slobodnog pada

Schematic view of the mass arrangement. The test masses are alternately Schematic view of the mass arrangement. The test masses are alternately connected to the balance by means of the “mass exchanger” and their weight connected to the balance by means of the “mass exchanger” and their weight

difference is determined. The field masses are moved between the two 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 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 masses and tidal forces are plotted for the two field-mass positions on the left

and right of the figure.and right of the figure.

     

The orbiting Lageos satellite monitors its position relative to the Earth using The orbiting Lageos satellite monitors its position relative to the Earth using reflected laser light. From the measured gravitational force between satellite and reflected laser light. From the measured gravitational force between satellite and ourour planet, an planet, and independently measuring G, one can calculate the mass of the d independently measuring G, one can calculate the mass of the

Earth.Earth.

fabry-perot eksperimentfabry-perot eksperiment

The apparatus used by the research group at the University of Washington, Seattle, to 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 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 attractiveness between a hanging plate (hidden inside the cylinder) and several spheres

which rotate about the cylinder.which rotate about the cylinder.

tačnost sata je uslovljena konstantnom vrednošću perioda oscilovanja tačnost sata je uslovljena konstantnom vrednošću perioda oscilovanja torzionog klatna za dati momenat inercijetorzionog klatna za dati momenat inercije