🔹 Very Short Answer (1 mark)
Q1. Define motion.
Ans. Motion is the change in position of a body with respect to time and a reference point.
Q2. What is rest?
Ans. A body is said to be at rest if its position does not change with respect to a reference point.
Q3. What is distance?
Ans. The total length of the path covered by an object.
Q4. What is displacement?
Ans. The shortest distance between initial and final position of a body in a specific direction.
Q5. What is speed?
Ans. Distance travelled per unit time.
Q6. What is velocity?
Ans. Displacement per unit time in a given direction.
Q7. Give SI unit of speed and velocity.
Ans. m/s (metre per second).
Q8. What is acceleration?
Ans. The rate of change of velocity per unit time.
Q9. What is retardation?
Ans. Negative acceleration (when velocity decreases with time).
Q10. What is uniform motion?
Ans. When a body covers equal distances in equal intervals of time.
🔹 Short Answer (2–3 marks)
Q11. Differentiate between distance and displacement.
Ans.
- Distance: Scalar, path length, always positive.
- Displacement: Vector, shortest path, can be zero/positive/negative.
Q12. Differentiate between speed and velocity.
Ans.
- Speed: Scalar, distance/time.
- Velocity: Vector, displacement/time.
Q13. What is uniform velocity?
Ans. A body has uniform velocity if it covers equal displacements in equal intervals of time in the same direction.
Q14. What is non-uniform motion?
Ans. When a body covers unequal distances in equal intervals of time.
Q15. Why is velocity a vector quantity?
Ans. Because it has both magnitude and direction.
Q16. Give the SI unit of acceleration.
Ans. m/s².
Q17. What is instantaneous speed?
Ans. Speed of an object at a particular instant of time.
Q18. Define average speed.
Ans. Total distance travelled divided by total time taken.
Q19. Define average velocity.
Ans. Total displacement divided by total time taken.
Q20. When is displacement equal to distance?
Ans. When a body moves along a straight line in the same direction without turning back.
🔹 Long Answer (4–5 marks)
Q21. Differentiate between uniform and non-uniform motion.
| Uniform Motion | Non-uniform Motion |
|---|---|
| Equal distance in equal time | Unequal distance in equal time |
| Speed/velocity constant | Speed/velocity changes |
| Eg: car on straight highway | Eg: bus in city traffic |
Q22. Why can displacement be zero but distance not zero?
Ans. If a body returns to its initial position, displacement = 0 but distance travelled is the total path length, hence not zero.
Q23. Explain acceleration with an example.
Ans. If a car’s velocity increases from 20 m/s to 30 m/s in 5 seconds, the rate of change of velocity is acceleration.
Q24. Differentiate between scalar and vector quantities.
| Scalar | Vector |
|---|---|
| Only magnitude | Magnitude + direction |
| Eg: Distance, Speed | Eg: Displacement, Velocity |
Q25. Write three equations of motion.
Ans.
- v = u + at
- s = ut + ½ at²
- v² – u² = 2as
(where u = initial velocity, v = final velocity, a = acceleration, s = displacement, t = time)
Q26. Explain uniform circular motion with an example.
Ans. Motion of a body in a circular path with constant speed is uniform circular motion. Eg: Moon around Earth.
Q27. Why is motion in a circle with constant speed considered accelerated motion?
Ans. Because the direction of velocity changes continuously, hence acceleration exists.
Q28. Differentiate between acceleration and retardation.
| Acceleration | Retardation |
|---|---|
| Velocity increases | Velocity decreases |
| Positive acceleration | Negative acceleration |
| Eg: Car speeding up | Car applying brakes |
Q29. Explain the motion of a freely falling body.
Ans. A body falling under the influence of gravity alone accelerates uniformly at 9.8 m/s², known as acceleration due to gravity (g).
Q30. State Newton’s graphical representation of motion.
Ans. A motion can be represented using distance-time and velocity-time graphs. They help to study nature of motion and calculate quantities like velocity, acceleration, displacement.
🔹 Case Study / Application-Based (5–6 marks)
Q31. A boy walks 2 km east and then 2 km west.
(i) What is his total distance?
(ii) What is his displacement?
Ans.
(i) Distance = 4 km.
(ii) Displacement = 0 km (final = initial).
Q32. A train moves with constant velocity for 1 hour. What type of motion is this?
Ans. Uniform motion.
Q33. Why do drivers slow down near a speed breaker? Which type of acceleration occurs?
Ans. They apply brakes → velocity decreases → retardation occurs.
Q34. Case Study – Cyclist in Circular Track
A cyclist moves with constant speed in a circular track.
(i) Is the velocity uniform?
(ii) Is he accelerated? Why?
Ans.
(i) No, velocity changes due to direction change.
(ii) Yes, acceleration is present.
Q35. A ball is thrown vertically upward.
(i) What happens to velocity at highest point?
(ii) What is acceleration throughout?
Ans.
(i) Velocity = 0 at top.
(ii) Acceleration = g downward everywhere.
Q36. A car moves 60 km in 1 hour, then 40 km in next 1 hour. Find average speed.
Ans. Average speed = total distance ÷ total time = 100 ÷ 2 = 50 km/h.
Q37. Why do distance-time graphs never slope downwards?
Ans. Because distance always increases with time, never decreases.
Q38. Why do velocity-time graphs help in calculating acceleration?
Ans. Slope of v–t graph gives acceleration.
Q39. A stone tied to a string is whirled in a circle and suddenly string breaks. In which direction will stone fly?
Ans. Tangential to the circle at that point.
Q40. Why do we need a reference point to describe motion?
Ans. Because motion is relative; an object may be in motion relative to one observer but at rest relative to another.
🔹 Extra Important (41–50)
Q41. What does the slope of distance-time graph represent?
Ans. Speed.
Q42. What does the slope of velocity-time graph represent?
Ans. Acceleration.
Q43. Area under velocity-time graph gives what?
Ans. Displacement.
Q44. What is the nature of distance-time graph for uniform motion?
Ans. Straight line.
Q45. What is the nature of velocity-time graph for uniform acceleration?
Ans. Straight line with slope.
Q46. What is the motion of a body when acceleration = 0?
Ans. Uniform motion (constant velocity).
Q47. Why is rest and motion relative terms?
Ans. Because an object may appear at rest with respect to one observer but in motion with respect to another.
Q48. Example of rectilinear motion.
Ans. A car moving on a straight road.
Q49. Example of periodic motion.
Ans. Pendulum motion, motion of Earth around Sun.
Q50. Example of oscillatory motion.
Ans. Vibration of a tuning fork, pendulum swing.