JEE Main 2014 — Gravitation Question with Solution
JEE Main 2014 (12 Apr Online)
Question
Two hypothetical planets of masses and are at rest when they are infinite distance apart. Because of the gravitational force they move towards each other along the line joining their centres. What is their speed when their separation is ' '? (Speed of is and that of is )
Choose an option
Show full solutionCorrect option: B
Correct answer
B
Step-by-step explanation
We choose reference point, infinity, where total energy of the system is zero.
So, initial energy of the system
Final energy
From conservation of energy, Initial energy Final energy
or
By conservation of linear momentum
or
Putting value of in equation (1), we get
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This is a previous-year question from JEE Main 2014, covering the Gravitation chapter of Physics. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.