1
Question Question A1
The following is the distance-time table of an object in motion:
| Time in seconds | Distance in meters |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 8 |
| 3 | 27 |
| 4 | 64 |
| 5 | 125 |
| 6 | 216 |
| 7 | 343 |
(a) What conclusion can you draw about the acceleration? Is it constant, increasing, decreasing, or zero?
(b) What do you infer about the forces acting on the object?
(a)
| Time (t) in s | Distance (s) in m | Velocity (v = s/t) in m/s | Acceleration (a = ∆v/∆t) in m/s |
|---|---|---|---|
| 0 | 0 | 0 | 0 |
| 1 | 1 | 1 | 1 |
| 2 | 8 | 4 | 3 |
| 3 | 27 | 9 | 5 |
| 4 | 64 | 16 | 7 |
| 5 | 125 | 25 | 9 |
| 6 | 216 | 36 | 11 |
| 7 | 343 | 49 | 13 |
We notice from the table above that the acceleration of the object is increasing.
(b) We know Force = mass x acceleration
As mass of the object remains same, the increasing acceleration implies that the force acting on the object is increasing as well.
BRIGHT TUTORIALS
BRIGHT TUTORIALS
CBSE Class IX | Academic Year 2026-2027
9403781999
Excellence in Education
Science | Chapter 8: Force and Laws of MotionWeb Content — Quick Reference
Chapter 8: Force and Laws of Motion — Quick Reference
Quick Revision Points
- Balanced forces: net force = 0, no acceleration. Unbalanced: net force ≠ 0, causes acceleration
- First Law (Inertia): object stays at rest/uniform motion unless external force acts
- Momentum p = mv (kg·m/s); Second Law: F = ma = Δp/Δt
- 1 N = force giving 1 kg an acceleration of 1 m/s²
- Third Law: every action has equal and opposite reaction (on different bodies)
- Conservation of momentum: m₁u₁ + m₂u₂ = m₁v₁ + m₂v₂ (no external force)
Exam Tips for Chapter 8
- Read the detailed chapter notes for complete coverage of all NCERT topics.
- Practice all NCERT in-text and back exercise questions — they are frequently asked in exams.
- Focus on comparison tables, diagrams, and definitions — these are high-scoring areas.
- For numericals (if applicable), practice at least 20 problems of varying difficulty.
- Refer to the practice question bank (200+ questions) for thorough preparation.
Related Resources
- Detailed Notes: ch08-force-and-laws-of-motion.html
- Practice Questions: 100+ questions with answers in 05-practice-questions/
- Chapter Test: 30-mark test paper in 06-tests/chapter-tests-30marks/
- Formula Sheet: Complete formula reference in 03-teacher-aid/formula-sheet.html
BRIGHT TUTORIALS
BRIGHT TUTORIALS
CBSE Class IX | Academic Year 2026-2027
9403781999
Excellence in Education
Science | Chapter 7: MotionWeb Content — Quick Reference
Chapter 7: Motion — Quick Reference
Quick Revision Points
- Distance (scalar, total path) vs Displacement (vector, shortest path)
- Speed = distance/time (scalar); Velocity = displacement/time (vector)
- Acceleration a = (v−u)/t; unit: m/s²
- Equations: v = u + at; s = ut + ½at²; v² = u² + 2as
- d-t graph slope = speed; v-t graph slope = acceleration; area under v-t = distance
- 1 km/h = 5/18 m/s; Free fall: u = 0, a = g = 9.8 m/s²
- Uniform circular motion: constant speed, changing velocity (direction changes)
Exam Tips for Chapter 7
- Read the detailed chapter notes for complete coverage of all NCERT topics.
- Practice all NCERT in-text and back exercise questions — they are frequently asked in exams.
- Focus on comparison tables, diagrams, and definitions — these are high-scoring areas.
- For numericals (if applicable), practice at least 20 problems of varying difficulty.
- Refer to the practice question bank (200+ questions) for thorough preparation.
Related Resources
- Detailed Notes: ch07-motion.html
- Practice Questions: 100+ questions with answers in 05-practice-questions/
- Chapter Test: 30-mark test paper in 06-tests/chapter-tests-30marks/
- Formula Sheet: Complete formula reference in 03-teacher-aid/formula-sheet.html