ICSE Class 10 Physics: Force — Laws of Motion & Complete Notes 2026

What is Force?

• Contact and non-contact forces; definition and SI unit (Newton)
• Balanced vs. unbalanced forces and their effects on state of motion
• Free body diagrams: drawing and interpreting force arrows

Newton's Three Laws of Motion

• First law (inertia): objects resist change in state unless acted upon by net force
• Second law: F = ma; relationship between force, mass and acceleration
• Third law: every action has an equal and opposite reaction; rocket propulsion example

Linear Momentum and Its Conservation

• Momentum p = mv; SI unit kg m/s
• Law of conservation of momentum applied to collision problems
• Explosion problems: two-body system momentum before and after

Friction — Types and Laws

• Static, kinetic and rolling friction; relative magnitudes
• Coefficient of friction μ = F/N; factors affecting friction
• Advantages of friction (walking, brakes) and disadvantages (wear and heat)

Uniform Circular Motion

• Centripetal force direction: always towards centre; not a new force
• Expression: F = mv²/r; deriving units
• Banking of roads and purpose of centripetal acceleration

Numericals Solved — Force Chapter

• Step-by-step: find acceleration when net force and mass are given
• Momentum change problems: impulse–momentum theorem
• Friction problems: minimum force required to move an object

Common Exam Mistakes and Tips

• Forgetting to state the direction of force in diagrams
• Confusing mass (kg) with weight (N) in calculations
• ICSE marking scheme: always show formula, substitution, and unit