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NEET2026PhysicsChapterActual

Two isolated point masses 2M and 5M are initially at rest in free space. They start moving towards each other strictly under mutual gravitational attraction. At a certain instant, if the mass 2M has moved a distance y , what is the distance covered by the mass 5M at that same instant?

Options

  1. A5y 2
  2. B2y 5
  3. C2y 7
  4. D5y 7

Correct answer

B. 2y 5

Step-by-step solution

Since no external force acts on the system of the two masses, the center of mass of the system remains at rest. Let the distance moved by the mass 2M be d₁ and the distance moved by the mass 5M be d₂ . From the conservation of the position of the center of mass: m₁ d₁ = m₂ d₂ Substituting the given values m₁ = 2M , m₂ = 5M , and d₁ = y : 2M y = 5M d₂ d₂ = 2y 5 The distance covered by the mass 5M is 2y 5 . Answer: 2y 5

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