Verified Solution • 2025–26 Session moderate

QJEEM19Ph7baa: JEE Main 2019 Physics - Class 11 JEEM19Ph7baa Solution: Two stars of masses 3 10 31 kg each, and at distance 2 10 11 m…

Two stars of masses 3 ×\times 1031 kg each, and at distance 2 ×\times 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 ×\times 10–11 Nm2 kg–2)

Multiple Choice Options

  • A 2.4 ×\times 104 m/s
  • B 1.4 ×\times 105 m/s
  • C 3.8 ×\times 104 m/s
  • D 2.8 ×\times 105 m/s

Step-by-Step Verified Solution

By energy convervation between 0 & ∞\infty .

−GMmr+−GMmr+12mV2=0+0- {{GMm} \over r} + {{ - GMm} \over r} + {1 \over 2}m{V^2} = 0 + 0

[M is mass of star m is mass of meteroite)

⇒\Rightarrow v =4GMr=2.8×105= \sqrt {{{4GM} \over r}} = 2.8 \times {10^5} m/s

Related Learning Resources & Exam Preparation

JEE Main PYQ Question Bank
Browse year-wise authentic previous years' questions with solutions
Authentic CBT Mock Tests
Simulate official exam environment with live timer and percentile scoring