Start learning →

CBSE Class 9 Gravitation — practice questions

Explore 50 free Gravitation questions in CBSE Class 9 Science. Open each question or exercise to read its content, reference answers and available explanation.

Practise Gravitation with Quill →

Gravitation questions and exercises with answers

Showing questions 1–30 of 50.

The universal gravitational constant $G$ has the SI value approximately:Read the answer and worked solution →For a satellite of mass $m$ orbiting Earth at radius $r$ (from the centre), the orbital velocity is:Read the answer and worked solution →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 the surface of Earth, acceleration due to gravity g equals:Read the answer and worked solution →At the centre of the Earth, the value of g is:Read the answer and worked solution →Escape velocity from Earth's surface is approximately:Read the answer and worked solution →The first cosmic velocity (orbital velocity at Earth's surface) is approximately:Read the answer and worked solution →At a height h above Earth's surface where h ≪ R, g' equals:Read the answer and worked solution →At depth d below Earth's surface, g' equals:Read the answer and worked solution →Gravitational potential energy of a mass m at the surface of Earth (taking U at infinity as zero):Read the answer and worked solution →Time period T of a satellite in orbit of radius r around Earth is (Kepler's 3rd law):Read the answer and worked solution →Acceleration due to gravity at the EQUATOR compared to that at the POLES:Read the answer and worked solution →Gravitational field strength I (also called g) at distance r from a point mass M:Read the answer and worked solution →For a satellite to be GEOSTATIONARY (stays over the same point on Earth), its orbital period must equal:Read the answer and worked solution →Two masses 6 kg and 3 kg are 2 m apart. Gravitational force between them (G = 6.67 × 10⁻¹¹):Read the answer and worked solution →If Earth shrinks to half its radius keeping mass constant, the new escape velocity becomes:Read the answer and worked solution →Kepler's second law states that the line joining a planet to the sun sweeps equal areas in equal times. This is equivalent to conservation of:Read the answer and worked solution →A satellite is in circular orbit at radius 2R from Earth's centre. Its orbital velocity in terms of v_surface = √(gR):Read the answer and worked solution →Total energy of a satellite in circular orbit equals:Read the answer and worked solution →Two planets orbit the same star with semi-major axes 1 AU and 4 AU. Ratio of their orbital periods T1 : T2 is:Read the answer and worked solution →Spot the value of g (gravity) that is wrongRead the answer and worked solution →The gravitational pull of the Earth on an object is its:Read the answer and worked solution →The acceleration due to gravity is denoted by:Read the answer and worked solution →The value of g near the Earth's surface is about:Read the answer and worked solution →The unit of g is the same as that of:Read the answer and worked solution →Weight is measured with a:Read the answer and worked solution →The gravitational force on an object acts:Read the answer and worked solution →A book on a table is pushed up by the:Read the answer and worked solution →The gravitational force on a mass m is written as:Read the answer and worked solution →

Worked practice questions

The universal gravitational constant $G$ has the SI value approximately:

  1. $6.67 \times 10^{-11}\,\mathrm{N\,m^2/kg^2}$
  2. $9.81\,\mathrm{m/s^2}$
  3. $6.022 \times 10^{23}\,\mathrm{/mol}$
  4. $1.6 \times 10^{-19}\,\mathrm{C}$
Show answer and solution

Correct answer: A. $6.67 \times 10^{-11}\,\mathrm{N\,m^2/kg^2}$

Universal gravitational constant $G = 6.67 \times 10^{-11}$ N·m²/kg² in SI units, the same everywhere in the universe. The units come from Newton's law $F = G m_1 m_2 / r^2$: $\dfrac{\text{kg} \cdot \text{kg}}{\text{m}^2} \cdot [G] = \text{N}$ so $[G] = \text{N} \cdot \text{m}^2 / \text{kg}^2$. Option B is the local acceleration due to gravity $g$ (not constant). Option C is Avogadro. Option D is the electronic charge.

Open this question →

For a satellite of mass $m$ orbiting Earth at radius $r$ (from the centre), the orbital velocity is:

  1. $v = \sqrt{\dfrac{GM}{r}}$
  2. $v = \sqrt{2 GM r}$
  3. $v = \dfrac{GM}{r^2}$
  4. $v = G M$
Show answer and solution

Correct answer: A. $v = \sqrt{\dfrac{GM}{r}}$

Set gravitational force equal to centripetal force on the satellite: $\dfrac{GMm}{r^2} = \dfrac{mv^2}{r}$ The $m$ cancels. Solve for $v$: $v^2 = \dfrac{GM}{r}$, so $v = \sqrt{\dfrac{GM}{r}}$. Orbital velocity at Earth's surface is about $7.9$ km/s (about 28,000 km/h). Option B looks similar but has a 2 inside the square root — that's the **escape velocity** $v_e = \sqrt{2GM/r}$, which is $\sqrt{2}$ times the orbital speed at the same radius. A textbook trap.

Open this question →

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
Show answer and solution

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.

Open this question →

How to practise

  1. Choose a Gravitation question and try to work out your answer.
  2. Open the question to check the correct answer and read its worked solution.
  3. Continue in the app for bite-sized lessons, explanations and review with Quill. You can start without creating an account.

Put it into practice

Continue with Gravitation practice for CBSE Class 9. Read explanations as you go. No signup form needed to start.

Practise Gravitation →

More Science topics

Diversity in Living OrganismsThe Fundamental Unit of LifeForce and Laws of MotionTissues: Plant and Animal TissuesWork and EnergyMatter in Our SurroundingsMotionAtoms and Molecules