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COMEDK Gravitation — practice questions — page 2

Explore 52 free Gravitation questions in COMEDK 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 31–52 of 52.

Total mechanical energy of a satellite escaping Earth from low orbit at radius R is:Read the answer and worked solution →Knock out the false gravity claimsRead 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

Total mechanical energy of a satellite escaping Earth from low orbit at radius R is:

  1. Negative
  2. Equal to potential energy at infinity
  3. Zero (at escape velocity)
  4. Positive
Show answer and solution

Correct answer: C. Zero (at escape velocity)

Escape velocity is defined as the speed at which total energy (KE + PE) equals zero, the boundary between bound (negative E) and free (positive E) trajectories. **So at escape conditions, total E = 0.**

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Knock out the false gravity claims

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Questions
  1. Question
    Three of these statements about escape velocity are false.
    Choices
    1. Explanation
      That figure is the orbital speed at the surface
      Item
      Escape speed from the surface is 7.9 km/s
    2. Item
      Escape speed from the surface is 11.2 km/s
      Correct
      Yes
    3. Explanation
      Escape speed is root two times the orbital speed
      Item
      Escape speed is twice the orbital speed
    4. Explanation
      The mass cancels, so the same speed frees any body
      Item
      Escape speed depends on the escaping mass
  2. Question
    Three of these statements about the value of g are false.
    Choices
    1. Explanation
      Earth bulges at the equator and spins, so g is smaller there
      Item
      g is larger at the equator than the poles
    2. Explanation
      Below the surface g falls as g times one minus d over R
      Item
      g grows steadily as you go deeper
    3. Item
      g at the centre of the Earth is zero
      Correct
      Yes
    4. Explanation
      G is a universal constant while g is a local acceleration
      Item
      g and G stand for the same quantity
Instructions
Three lines in each round are wrong. Tap those three and leave the one that stands.
_Source: Qallery verified question bank, COMEDK UGET, topic Gravitation_

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Conserved, or not conserved?

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Items
  1. Item
    Angular momentum
    Category
    Conserved
  2. Item
    Total mechanical energy
    Category
    Conserved
  3. Item
    Kinetic plus potential energy
    Category
    Conserved
  4. Item
    Linear momentum
    Category
    Not conserved
  5. Item
    The product of mass and velocity
    Category
    Not conserved
Categories
  1. Item
    Conserved
  2. Item
    Not conserved
Under gravity, angular momentum and total mechanical energy are conserved, but linear momentum is NOT. Source: syllabus Physics, Ch 7 Gravitation.

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