Looking for reliable SEBA Class 9 Science Chapter 8 (Motion) extra questions and answers for the 2026–27 academic year? Access important additional practice questions, solved physics numericals, graphical analysis problems, equation derivations, and short conceptual notes designed to help you score top marks in your annual exams.
Extra question and answer
1. What is motion? Give one example.
Answer: Motion is the change in position of an object with time.
Example: Birds flying in the sky.
2. Why don’t we feel the motion of the Earth?
Answer: Because Earth moves very smoothly and we move along with it.
3. What is meant by a reference point?
Answer: A fixed point chosen to describe the position of an object.
Example: School is 2 km north of the railway station.
4. Define distance.
Answer: Distance is the total path covered by an object.
5. Define displacement.
Answer: Displacement is the shortest distance between the initial and final positions, along with direction.
6. Can displacement be zero? Give an example.
Answer: Yes. If an object returns to its starting point.
Example: O → A → O → displacement = 0.
7. Define uniform motion.
Answer: An object is in uniform motion when it covers equal distances in equal intervals of time.
8. Define non-uniform motion.
Answer: Motion in which unequal distances are covered in equal time intervals.
What is speed? Give its formula.Ans. Speed is the distance travelled per unit time.
Formula: v = s / t
10. Define average speed.
Answer: Average speed = Total distance ÷ Total time taken.
SEBA Class 9 Science Chapter 8 Extra Questions
11. What is velocity?
Answer: Velocity is speed in a given direction.
What is average velocity (uniform acceleration)?Ans. Average velocity = (u + v) / 2
What is acceleration?Ans. Rate of change of velocity.
Formula: a = (v – u) / t
14. What is negative acceleration?
Answer: When velocity decreases with time (retardation).
15. What is the unit of speed and velocity?
Answer: m/s, km/h.
16. What is the unit of acceleration?
Answer: m/s².
17. What does a straight line in a distance-time graph show?
Answer: Uniform motion.
18. What does a horizontal line in a distance-time graph show?
Answer: Object is at rest.
19. What does the slope of a distance-time graph represent?
Answer: Speed of the object.
20. What does the area under a velocity-time graph represent?
Answer: Displacement (distance travelled).
Class 9 Science Chapter 8 Important Questions SEBA 2026-27
21. Differentiate between distance and displacement.
| Distance | Displacement |
| Total path covered | Shortest path between initial and final point |
| Scalar | Vector |
| Never zero | Can be zero |
22. Explain with an example that motion is relative.
Motion depends on who observes it.
A passenger inside a bus finds other passengers at rest, but a person outside sees them moving.
23. Give one example each of uniform and non-uniform motion.
Uniform: A car moving on a straight road at constant speed.
Non-uniform: A car moving in traffic.
24. Explain why velocity changes in non-uniform motion.
Because speed may increase or decrease and direction may change.
25. Define speed, velocity, and acceleration.
Speed – Distance/time
Velocity – Speed with direction
Acceleration – Rate of change of velocity
26. When is acceleration zero?
When velocity does not change (uniform motion).
27. Give an example of positive acceleration and negative acceleration.
Positive: Car speeding up.
Negative: Car slowing down when brakes are applied.
28. Explain distance–time graph for uniform motion.
It is a straight line showing equal distance covered in equal time.
29. Explain distance–time graph for non-uniform motion.
It is a curved line showing changing speed with time.
30. What is the use of velocity–time graphs?
To find acceleration and displacement.
Motion Class 9 SEBA Extra Question Answer
31. What does a horizontal line in a velocity–time graph represent?
Uniform velocity.
32. How can you find displacement using a velocity–time graph?
By calculating the area under the graph line and the time axis.
33. What do you understand by uniform acceleration?
Velocity increases by equal amounts in equal intervals of time.
34. Give the SI units of speed, velocity, and acceleration.
Speed – m/s
Velocity – m/s
Acceleration – m/s²
35. Explain with example: displacement may be less than distance.
O → A → C
Distance: O–A + A–C
Displacement: O–C (straight)
So displacement < distance.
36. Why do we need graphs in the study of motion?
They help in understanding changes clearly and quickly.
37. What does the slope of velocity–time graph give?
Acceleration.
38. A cyclist moves from 0 to 6 m/s in 30 s. Find acceleration.
Ans.
a = (6 – 0) / 30
a = 0.2 m/s²
39. A car slows from 6 m/s to 4 m/s in 5 s. Find acceleration.
Ans.
a = (4 – 6) / 5
a = -0.4 m/s² (Negative acceleration / retardation)
40. A car travels 100 km in 2 hours. Find speed.
Speed = 100 ÷ 2 = 50 km/h.
SEBA Class 9 Science Chapter 8 Solved Numericals
41. Explain uniform and non-uniform motion with graphs.
Uniform motion: Distance-time graph is a straight line.
Non-uniform motion: Distance-time graph is curved.
Uniform → speed constant
Non-uniform → speed changes
42. Derive the formula for acceleration.
Ans.
Acceleration = change in velocity / time
= (final velocity – initial velocity) / time
a = (v – u) / t
43. Describe positive acceleration, negative acceleration, and zero acceleration with examples.
Positive: Speed increases (car speeding up).
Negative: Speed decreases (braking).
Zero: Constant speed (moving with same velocity).
44. Explain motion with respect to reference point using examples.
Everything moves relative to a reference point.
Example: Passenger inside bus (others at rest)
Person outside bus (passengers moving)
45. Explain displacement using a velocity–time graph.
Area under velocity–time graph = displacement
Example: For uniform velocity, displacement = area of rectangle.
46. Explain the importance of average speed.
Objects rarely move with constant speed.
Average speed gives a true measure of total journey.
Useful in travel, sports, and physics calculations.
47. Show graphically: motion at rest, uniform speed, and non-uniform speed.
Rest → horizontal distance-time line
Uniform → straight rising line
Non-uniform → curved line
48. Explain how acceleration is shown on a velocity–time graph.
Uniform acceleration: straight sloping line
Non-uniform acceleration: curved line
Horizontal line: no acceleration
Class 9 Science Motion Practice Questions
49. Explain the bicycle example for acceleration.
0 → 6 m/s in 30 s → a = 0.2 m/s²
6 → 4 m/s in 5 s → a = –0.4 m/s²
Shows both acceleration and retardation.
🔬 Updated Extra Questions Guide Notice: This page features an extensive collection of SEBA Class 9 Science Chapter 8 (Motion) Extra Questions, Solved Numericals, and Conceptual Answers updated for the 2026–27 academic session. All physics formulas, graph interpretations, and additional practice problems strictly follow the latest revised Assam Board (SEBA) curriculum.
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