🌍 Gravitation – Class 9 Science MCQs

Section 2: Acceleration due to Gravity & Free Fall (Q26–Q50)

Q26. Acceleration due to gravity on Earth is denoted by:

A. g
B. G
C. F
D. a

✅ Correct Answer: A. g

Explanation:

• g → acceleration due to gravity (≈ 9.8 m/s² on Earth).
• G → universal constant.
• F → force.
• a → general acceleration.

Q27. Average value of g on Earth’s surface is:

A. 8.8 m/s²
B. 9.8 m/s²
C. 10.8 m/s²
D. 11.8 m/s²

✅ Correct Answer: B. 9.8 m/s²

Q28. The SI unit of g is:

A. N/kg
B. m/s²
C. N m²/kg²
D. J

✅ Correct Answer: B. m/s²

Explanation:

• Acceleration is measured in m/s².

Q29. The formula for acceleration due to gravity is:

A. g = Gm/r²
B. g = GM/R²
C. g = F/m
D. g = ma

✅ Correct Answer: B. g = GM/R²

Explanation:

• g=GMR2g = \dfrac{GM}{R^2}, where M = Earth’s mass, R = radius.

Q30. Value of g on Moon is:

A. 1/6 of Earth
B. 1/2 of Earth
C. Equal to Earth
D. Twice of Earth

✅ Correct Answer: A. 1/6 of Earth

Q31. Acceleration due to gravity depends on:

A. Mass of body
B. Mass and radius of Earth
C. Shape of body
D. Velocity of body

✅ Correct Answer: B. Mass and radius of Earth

Explanation:

• g = GM/R² → independent of mass of falling body.

Q32. Which of the following quantities is same for all bodies during free fall?

A. Velocity
B. Acceleration
C. Momentum
D. Kinetic energy

✅ Correct Answer: B. Acceleration

Explanation:

• All bodies fall with same acceleration g (Galileo’s experiment).

Q33. Which factor does not affect value of g?

A. Mass of falling body
B. Altitude
C. Depth
D. Latitude

✅ Correct Answer: A. Mass of falling body

Q34. The value of g decreases if we go:

A. Up (higher altitude)
B. Inside Earth (depth)
C. Towards equator from poles
D. All of the above

✅ Correct Answer: D. All of the above

Q35. Free fall means:

A. Fall with air resistance
B. Fall under gravity alone
C. Fall with constant velocity
D. Fall with friction

✅ Correct Answer: B. Fall under gravity alone

Q36. During free fall, acceleration of body is:

A. Zero
B. Constant and equal to g
C. Decreasing
D. Increasing

✅ Correct Answer: B. Constant and equal to g

Q37. A body falls freely from rest. After 3 s, velocity = ? (g = 10 m/s²)

A. 10 m/s
B. 20 m/s
C. 30 m/s
D. 40 m/s

✅ Correct Answer: C. 30 m/s

Explanation:

• v = gt = 10 × 3 = 30.

Q38. Distance fallen by freely falling body in 2 s (g = 10 m/s²) = ?

A. 10 m
B. 20 m
C. 25 m
D. 30 m

✅ Correct Answer: C. 20 m

Correction:

• s=12gt2=0.5×10×4=20ms = \tfrac{1}{2} g t^2 = 0.5 × 10 × 4 = 20 m.
  ✅ Correct Answer: B. 20 m

Q39. The velocity with which a body falls freely after time t is:

A. v = u + at
B. v = gt
C. v = ut
D. v = at²

✅ Correct Answer: B. v = gt

Explanation:

• For free fall, u = 0, a = g → v = gt.

Q40. Distance travelled in nth second of free fall = ?

A. ½ g t²
B. g(2n – 1)/2
C. g(n² – 1)
D. 2gn

✅ Correct Answer: B. g(2n – 1)/2

Q41. A stone falls freely for 5 s (g = 10 m/s²). Distance covered = ?

A. 100 m
B. 125 m
C. 150 m
D. 200 m

✅ Correct Answer: C. 125 m

Explanation:

• s = ½ gt² = 0.5 × 10 × 25 = 125.

Q42. Time taken by a body to fall 45 m (g = 10 m/s²)?

A. 2 s
B. 3 s
C. 4 s
D. 5 s

✅ Correct Answer: B. 3 s

Explanation:

• s = ½ gt² → 45 = 5t² → t² = 9 → t = 3.

Q43. If g at Earth’s surface is 9.8 m/s², what is g at height equal to Earth’s radius?

A. 9.8 m/s²
B. 4.9 m/s²
C. 2.45 m/s²
D. 0

✅ Correct Answer: B. 2.45 m/s²

Explanation:

• At h = R, g’ = g/4.

Q44. Which statement is correct?

A. All bodies fall at same rate in vacuum
B. Heavy body falls faster than light in vacuum
C. Light body falls faster in vacuum
D. None

✅ Correct Answer: A. All bodies fall at same rate in vacuum

Explanation:

• Galileo proved acceleration is independent of mass.

Q45. The force with which Earth attracts 1 kg mass near its surface = ?

A. 1 N
B. 9.8 N
C. 10 N
D. 98 N

✅ Correct Answer: B. 9.8 N

Explanation:

• F = mg = 1 × 9.8.

Q46. The value of g is maximum at:

A. Poles
B. Equator
C. Centre of Earth
D. Moon

✅ Correct Answer: A. Poles

Explanation:

• Due to rotation, bulge at equator reduces g.

Q47. The value of g is zero at:

A. Equator
B. Poles
C. Centre of Earth
D. Mountains

✅ Correct Answer: C. Centre of Earth

Explanation:

• Net gravitational pull cancels out.

Q48. The motion of freely falling body is an example of:

A. Uniform motion
B. Uniformly accelerated motion
C. Oscillatory motion
D. Random motion

✅ Correct Answer: B. Uniformly accelerated motion

Q49. The acceleration due to gravity on Moon is approximately:

A. 1.6 m/s²
B. 3.2 m/s²
C. 4.9 m/s²
D. 9.8 m/s²

✅ Correct Answer: A. 1.6 m/s²

Q50. Which of these was first shown by Galileo’s Leaning Tower of Pisa experiment?

A. Heavy bodies fall faster
B. Light bodies fall faster
C. All bodies fall with same acceleration
D. Motion is relative

✅ Correct Answer: C. All bodies fall with same acceleration

Gravitation Class 9 Science, CBSE Class 9 Science MCQs, NCERT Class 9 gravitation questions, Class 9 Science exam practice, Online learning Science Class 9, gravitation class 9 science mcqs with answers, cbse class 9 science gravitation multiple choice questions, ncert class 9 gravitation quiz online, important mcqs for cbse class 9 science gravitation chapter, gravitation class 9 mcqs for online learning