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SCIENCE IMPORTANT FORMULAE CLASS - 9

Important Formulae for class 9 science
Updated for new syllabus - 2026

CBSENCERTFORMULAE

Class 9 science Important Formulae

The Important Science Formulae section at Saraswat Academy provides a complete collection of chapter-wise scientific formulas based on the latest CBSE Syllabus 2026–27. These formulas are carefully selected from the NCERT textbooks and presented in a simple, easy-to-understand format for quick learning and revision. They help students strengthen their conceptual understanding, solve numerical problems accurately, and improve problem-solving speed in Physics, Chemistry, and other formula-based topics. Regular practice of these formulas is essential for homework, class tests, unit tests, practical examinations, half-yearly examinations, annual examinations, and CBSE board examinations. This page serves as a quick revision resource, enabling students to recall important formulas confidently and perform better in both school and competitive examinations.

Regular revision of scientific formulas helps students strengthen conceptual understanding, improve numerical problem-solving skills, and reduce errors in calculations during examinations. Whether you are preparing for school assessments, practical examinations, or CBSE board exams, these chapter-wise science formula sheets provide a quick and effective revision resource. Students are encouraged to practise these formulas alongside NCERT questions, exemplar problems, practical-based questions, competency-based questions, and previous years' board questions to develop scientific reasoning, enhance accuracy, and achieve excellent marks in Science.

Important Formulae: Science Class - 9
Chapter - 4



Important Formulae - Chapter 4: Describing Motion Around Us


1. Average Speed

Formula

Average Speed = Total Distance Travelled ÷ Time Interval

Symbol Form
Average Speed = Distance / Time

SI Unit: m/s


2. Average Velocity

Formula

Average Velocity = Displacement ÷ Time Interval

Symbol Form
v = s / t

SI Unit: m/s


3. Average Acceleration

Formula

Average Acceleration = Change in Velocity ÷ Time Interval

Symbol Form
a = (v − u) / (t₂ − t₁)

or

a = (Final Velocity − Initial Velocity) ÷ Time

SI Unit: m/s²


4. Change in Velocity

Change in Velocity = Final Velocity − Initial Velocity

Δv = v − u


5. Displacement

Displacement = Final Position − Initial Position

Δs = s₂ − s₁


6. Slope of Position-Time Graph

Velocity = Slope of Position-Time Graph

Slope = Change in Position ÷ Change in Time

Slope = (s₂ − s₁) ÷ (t₂ − t₁)


7. Slope of Velocity-Time Graph

Acceleration = Slope of Velocity-Time Graph

Slope = Change in Velocity ÷ Change in Time

Slope = (v₂ − v₁) ÷ (t₂ − t₁)


8. Distance from Velocity-Time Graph

Distance (or Displacement) = Area under the Velocity-Time Graph


9. Conversion of Speed

1 km/h = 5/18 m/s

m/s = (5/18) × km/h


1 m/s = 18/5 km/h

km/h = (18/5) × m/s


10. Acceleration Due to Gravity

g = 9.8 m/s²


Important SI Units

Physical Quantity SI Unit
Distance metre (m)
Displacement metre (m)
Time second (s)
Speed m/s
Velocity m/s
Acceleration m/s²

Quick Revision Formulae

  • Average Speed = Total Distance ÷ Time
  • Average Velocity = Displacement ÷ Time
  • a = (v − u) ÷ t
  • a = (v − u) ÷ (t₂ − t₁)
  • Displacement = Final Position − Initial Position
  • Velocity = Slope of Position-Time Graph
  • Acceleration = Slope of Velocity-Time Graph
  • Distance = Area under Velocity-Time Graph
  • 1 km/h = 5/18 m/s
  • 1 m/s = 18/5 km/h
  • g = 9.8 m/s²