JEE Main 2020PhysicsGravitationHardMCQ

JEE Main 2020 — Gravitation Question with Solution

JEE Main 2020 (06 Sep Shift 2)

Question

Two planets have masses M and 16 M and their radii are a and 2a, respectively. The separation between the centres of the planets is 10a. A body of mass m is fired from the surface of the larger planet towards the smaller planet along the line joining their centres. For the body to be able to reach at the surface of smaller planet, the minimum firing speed needed is :

Choose an option

Show full solutionCorrect option: D
Correct answer
D325GMa

Step-by-step explanation

  

12mu2+-G×10Mm2a-GMm8a=0-G×16Mm8a-GM×m2a

⇒u=45GM4a

u=325GMa

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About this question

This is a previous-year question from JEE Main 2020, 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.