Class 9 Science Chapter 6, How Forces Affect Motion, picks up where Chapter 4 stopped: Chapter 4 described motion, this chapter asks what causes it to change. It covers force and its measurement, balanced and unbalanced forces, friction and Newton’s three laws of motion.
What Class 9 Science Chapter 6 Covers
6.1 and 6.2 Force revise what a force can do (start motion, change speed or direction, change shape) and how its magnitude is measured, then separate balanced from unbalanced forces.
6.3 The Force of Friction treats friction as a force that is often overlooked but always present, acting opposite to the motion.
6.4 to 6.6 Newton’s Laws of Motion state the first law (inertia), the second law (net force and change in motion) and the third law (action and reaction), with worked examples.
6.7 Forces Acting on a System of Objects applies the laws to objects that move together.
Exercises in Chapter 6
- Revise, Reflect, Refine problems on all three laws.
- The Journey Beyond: two toy cars with bar magnets to see action and reaction, and a rope wrapped around a rough branch to feel friction.
Read Class 9 Science Chapter 6 Online
More Chapters
- Previous: Chapter 5: Exploring Mixtures and their Separation
- Next: Chapter 7: Work, Energy, and Simple Machines
- Hindi medium: Class 9 Science Chapter 6 PDF in Hindi (Anveshan)
- All Science chapters and the other Class 9 books: Class 9 NCERT books 2026-27
FAQ
What are Newton’s three laws of motion?
First: an object stays at rest or in uniform motion unless a net force acts on it. Second: a net force changes the motion of an object in proportion to the force. Third: when one object exerts a force on another, the second exerts an equal and opposite force on the first.
Is friction in Class 9 Science?
Yes, in Chapter 6, section 6.3.