A satellite is in a circular orbit very close to the surface of a spherical planet. The period of the orbit is 2.17 hours. What is density of the planet

Respuesta :

Explanation:

Lets consider

Circumference of orbit = T

as it is mentioned in the question that a satellite is in orbit that is very close to the surface of planet. so

circumference of orbit = circumference of planet

Time period = T

radius of planet = R

orbital velocity = V

gravitational constant = G

mass of planet = m

Solution:

Time period for a uniform circular motion of orbit is,

T = [tex]\frac{2\pi R}{V}[/tex]

[tex]T = \frac{2\pi R }{\sqrt{\frac{GM}{R} } }[/tex]

[tex]T= 2\pi \sqrt{(\frac{R^3}{GM} )}[/tex]

[tex]M = \frac{4}{3} \pi R^{3}p[/tex]

where p = density

[tex]T = 2\pi \sqrt{\frac{R^{3} }{G\frac{4}{3}\pi R^{3} p } }[/tex]

[tex]T = \sqrt{\frac{3\pi }{Gp} }[/tex]

T = 2.17 hours = 7812 sec

(7812)² = [( 3×3.14)/6.67×[tex]10^{-11}[/tex]×ρ)]

ρ = 6.28/6.67×[tex]10^{-11}[/tex]×6.10×[tex]10^{-7}[/tex]

ρ = 6.28/40.687×[tex]10^{-18}[/tex]

ρ = 0.1543×[tex]10^{18}[/tex]kg/m³

ρ = 15.43×[tex]10^{16}[/tex]kg/m³