JEE MainPhysicsGravitationMCQ+4 / −1
Two stars of masses 3 1031 kg each, and at distance 2 1011 m rotate in a plane about their common centre of mass O. A meteorite passes through O moving perpendicular to the star’s rotation plane. In order to escape from the gravitational field of this double star, the minimum speed that meteorite should have at O is - (Take Gravitational constant; G = 6.67 10–11 Nm2 kg–2)
- A2.4 104 m/s
- B1.4 105 m/s
- C3.8 104 m/s
- D2.8 105 m/s
View written solutionFree
Correct answer: D
- Understand the configuration
Two identical stars each have mass and the distance between them is So each star is at distance from the common centre of mass .
The meteorite passes through along a direction perpendicular to the plane of rotation.
- Gravitational potential at the centre
Potential due to one star at distance is Since there are two identical stars, total potential at is
Substitute values:
- Condition for escape
For minimum escape speed, total mechanical energy at must be zero:
So,
Hence,
Therefore,
- Calculate the value
- Match with options
So the correct option is:
D:
- Comparison with stored correct answer
Stored correct answer: D
My derived answer: D
They agree.
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