Question #0091d

1 Answer
Dec 1, 2016

Let

#m->"mass of satellite" #

#M->"mass of Earth" #

#R->"radius of the orbit of the satellite" #

#G->"Gravitational constant" #

#T->"time period of satellite" #

#omega->"angular speed of satellite"=(2pi)/T #

The centripetal force (#F_c#) acting on the satellite revolving round the Earth along the orbit having radius R is given by

#F_c=momega^2R#

The gravitaional force #(F_g)# acting on the satellite will provide the required centripetal force.

#F_g=G(mM)/R^2#

Now #F_c=F_g#

#=>momega^2R=(GmM)/R^2#

#=>((2pi)/T)^2R=(GM)/R^2#

#=>T^2=((4pi^2)/(GM))R^3....... (1)#

Now differentiating (1) w.r to R we get

#=>2TdT=((4pi^2)/(GM))*3R^2dR........(2)#

Dividing (2) by (1) we get

#2(dT)/T=(3dR)/R#

#=>(dT)/T=3/2((dR)/R)......(3)#

Now by the problem change in radius of the satellite is
#dR=1.02R-R=0.02R#

Inserting this value of #dR=0.02R# in equation (3) we get the percentage change in time period of second satellite w.r to the time period of first satellite.

#"% change in time period"#

#=(dT)/Txx100%=3/2((0.02R)/R)xx100%#

#=3%#