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Indian Navy INET Gravitation — practice questions

Explore 26 free Gravitation questions in Indian Navy INET Physics. Open each question or exercise to read its content, reference answers and available explanation.

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Gravitation questions and exercises with answers

Showing questions 1–26 of 26.

The escape velocity from the Earth's surface is approximately ($R = 6.4 \times 10^6$ m, $g = 9.8$ m/s²):Read the answer and worked solution →Newton's law of gravitation states the force between two masses is:Read the answer and worked solution →At depth d below Earth's surface, g' equals:Read the answer and worked solution →At what point on the line joining Earth and Moon is the net gravitational field zero? (M_E = 81 M_moon)Read the answer and worked solution →As per your syllabus, the escape speed from the Moon's surface is approximately which?Read the answer and worked solution →As per your syllabus, the gravitational potential energy is a scalar quantity with dimensions which?Read the answer and worked solution →Conserved, or not conserved?Read the answer and worked solution →True or false: conservation under gravityRead the answer and worked solution →Complete the weightlessness explanationRead the answer and worked solution →True or false: weightlessnessRead the answer and worked solution →Kepler's third lawRead the answer and worked solution →Assertion and reasonRead the answer and worked solution →Two are true, one is notRead the answer and worked solution →Three of these are wrong. Find the one that holds.Read the answer and worked solution →Tap every quantity conserved for orbital motionRead the answer and worked solution →Flip and pair: law with what it saysRead the answer and worked solution →Spot the one that does not belongRead the answer and worked solution →Order the reasoning: why an astronaut floatsRead the answer and worked solution →True or false: Kepler's lawsRead the answer and worked solution →Which law is being described?Read the answer and worked solution →Orbits and satellitesRead the answer and worked solution →Tap every true statement about orbital motionRead the answer and worked solution →Complete Kepler's third lawRead the answer and worked solution →Spot the one that does not belongRead the answer and worked solution →Flip and pair: statement with its subjectRead the answer and worked solution →Assertion and reason: orbitsRead the answer and worked solution →

Worked practice questions

The escape velocity from the Earth's surface is approximately ($R = 6.4 \times 10^6$ m, $g = 9.8$ m/s²):

  1. $7.9$ km/s
  2. $11.2$ km/s
  3. $20$ km/s
  4. $1000$ m/s
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Correct answer: B. $11.2$ km/s

Escape velocity from Earth's surface: $v_e = \sqrt{2gR}$ (using the surface relation $GM/R^2 = g$). $v_e = \sqrt{2 \times 9.8 \times 6.4 \times 10^6} = \sqrt{1.25 \times 10^8} \approx 1.12 \times 10^4$ m/s $= 11.2$ km/s. Option A ($7.9$ km/s) is the *orbital* velocity at Earth's surface, smaller by a factor of $\sqrt{2}$. That trap is identical to the one in the orbital-velocity question.

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Newton's law of gravitation states the force between two masses is:

  1. Repulsive
  2. Proportional to distance
  3. Attractive, inversely proportional to square of distance
  4. Independent of mass
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Correct answer: C. Attractive, inversely proportional to square of distance

F = G m1 m2 / r². Always attractive, follows inverse square law. Direction along the line joining the centres.

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At depth d below Earth's surface, g' equals:

  1. g (1 - d²/R²)
  2. g (1 - d/R)
  3. g (1 + d/R)
  4. g (R/d)
Show answer and solution

Correct answer: B. g (1 - d/R)

For a uniform Earth, g' = g (1 - d/R). **So g decreases linearly with depth, reaching zero at the centre (d = R).**

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