Q 11 :

Two satellites A and B move round the earth in the same orbit. The mass of A is twice the mass of B. The quantity which is same for the two satellites will be      [2023]

  • Potential energy

     

  • Total energy

     

  • Kinetic energy

     

  • Speed

     

(4)

P.E.=-GMpMAR

K.E.=+GMpMA2R

T.E.=-GMpMA2R

Speed =v=GMpR

Speed of satellite is independent of mass of satellite.



Q 12 :

Initially a satellite of 100 kg is in a circular orbit of radius 1.5RE . This satellite can be moved to a circular orbit of radius 3RE  by supplying α×106 J of energy. The value of α is______. 

(Take Radius of Earth RE=6×106m and  𝑔=10m/s2)        [2026]

  • 100

     

  • 500

     

  • 1000

     

  • 150

     

(3)

Energy of a satellite in a circular orbit is given as

E=-GMEm2r ;  r=radius of circular orbit

Required energy to be supplied=ΔE=Ef-Ei

ΔE=(-GMEm2(3RE))-(-GMEm2(1.5RE))

       =GMEm6RE

Now,  g=GMERE2GMERE=gRE

  ΔE=16gmRE

                 =16×10×100×6×106

                  =1000×106

α=1000