8.4 Io, one of the satellites of Jupiter, has an orbital period of 1.769 days and the radius of the orbit is 4.22 × 108 m. Show that the mass of Jupiter is about one-thousandth that of the sun.
Orbital period ofI0,
TIo=1.769days×24×60×60 s
Orbital radius of Io,
RIo=4.22×108M
Satellite Iois revolving around the Jupiter
Mass of the latter is given by the relation:
MJ=4π2R3T2Io ...(i)
Where,
MJ= Mass of Jupiter
G = Universal gravitational constant
The orbital radius of the Earth,
Te=365.25 days=365.25×24×60×60 s
The orbital radius of the Earth,
Re=1 AU=1.496×1011 m
Mass of sun is given as:
Ms=4π2R3GT2e ...(ii)
From (i) and (ii),
MsMJ=4π2R3eGT2e×GT2Io4π2R3Io=R3eRIo×T2IoT2e
=(1.769×24×60×60365.25×24×60×60)2×(1.496×10114.22×108)3
=1045.04
=1000 (Approx.)
⇒ MsMJ=1000
⇒ Ms=1000×MJ
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