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JEE Main 201910 JanuaryMorning Shift
Exam
JEE Main
Year
2019
Date
10 January
Shift
Morning Shift
Subject
Physics
Chapter
Gravitation

JEE Main 2019 · 10 January · Morning Shift · Physics · Gravitation

A satellite is moving with a constant speed v in circular orbit...

A satellite is moving with a constant speed vv in circular orbit around the earth. An object of mass 'm' is ejected from the satellite such that it just escapes from the gravitational pull of the earth. At the time of ejection, the kinetic energy of the object is:

Options

  1. A32mv2\dfrac{3}{2}m{v}^{2}
  2. Bmv2m{v}^{2}
  3. C12mv2\dfrac{1}{2}m{v}^{2}
  4. D2mv22m{v}^{2}

Correct answer

B. mv2m{v}^{2}

Step-by-step solution

At height rr from the centre of the Earth, orbital velocity is given as:

orbitalvelocity=GMrorbitalvelocity = \sqrt{\dfrac{GM}{r}}

Ve=2v{V}_{e} = \sqrt{2}v

K.E=12m(2v)2=mv2K . E = \dfrac{1}{2}m{\left(\sqrt{2}v\right)}^{2} = m{v}^{2}

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