How Forces Affect Motion

Chapter at a glance

What forces are, balanced and unbalanced forces, friction, Newton’s three laws of motion, and how to treat several objects together as one system.

What this chapter covers

• 6.1 The Concept of Force
• 6.2 Balanced and Unbalanced Forces
• 6.3 The Force of Friction
• 6.4 Newton’s First Law of Motion
• 6.5 Newton’s Second Law of Motion
• 6.6 Newton’s Third Law of Motion
• 6.7 Forces Acting on a System of Objects

Key points

• Friction acts opposite to the direction of motion.
• First law: without a net force, an object stays at rest or moves with constant velocity.
• Second law: acceleration is along the net force, proportional to it and inversely proportional to mass (F = ma).
• Third law: forces between two objects are equal and opposite.

Read the NCERT chapter

Read this chapter in the official NCERT textbook Exploration (2026-27 edition) for free on ncert.nic.in.

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