Engineering
Physics
Keplers Law
Gravitational Force and Field
Artificial Satellites
Question

There is a hollow spherical planet of inner radius R1 and outer radius R2 and uniform mass density ρ. If the frequency of revolution of a satellite revolving around the planet in an orbit of radius 5R is given by f=[(1+1N2)Gρ15π]1/2 . Find the value of N.

(Given : R1 = R, R2 = 3R)

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Solution

Fg=mEg=mv025R

⇒v025R=G(5R)2[ρ43π(3R)3−ρ43πR3]

⇒v0=[4πGρR23(265)]1/2

∴f=v02π(5R)=[26125Gρ3π]1/2

=[(1+152)Gρ15π]1/2