NEET2009PhysicsGravitationActual
Two satellites of earth, S₁ and S₂ , are moving in the same orbit. The mass of S₁ is four times the mass of S₂ . Which one of the following statements is true?
Options
- AThe time period of S₁ is four times that of S₂
- BThe potential energies of earth and satellite in the two cases are equal
- CS₁ and S₂ are moving with the same speed
- DThe kinetic energies of the two satellites are equal
Correct answer
C. S₁ and S₂ are moving with the same speed
Step-by-step solution
When two satellites of earth are moving in same orbit, then time period of both are equal. From Kepler's third law T^2 r^3 Time period is independent of mass, hence their time periods will be equal. The potential energy and kinetic energy are mass dependent, hence the PE and KE of satellites are not equal. But, if they are orbiting in a same orbit, then they have equal orbital speed.