Newton's First Law of Motion

Introduction

• Newton's First Law of motion, also known as the law of inertia, is one of the fundamental principles of physics. It describes the behaviour of objects when all existing forces acting on them are balanced.

Statement of the First Law

• Newton's First Law states that objects with balanced forces acting on them will remain at rest or in constant motion with a constant velocity. In simpler terms, an object will not change its state of motion unless an unbalanced force acts upon it.

Key Concepts

• Balanced Forces: When the forces acting on an object are balanced, the object experiences no net force, and its motion remains unchanged.
• Rest or Constant Motion: If an object is initially at rest, it will stay at rest as long as the forces acting on it are balanced. Similarly, if an object is in constant motion in a straight line, it will continue moving at a constant velocity in the absence of unbalanced forces.

Newton's Insight

• Sir Isaac Newton discovered that objects tend to maintain their state of motion. This means that an object at rest will stay at rest, and an object in motion will continue moving in a straight line at a constant speed unless a net force acts on it.

Implications of the First Law

• The First Law implies that:
  • Forces act on objects: Forces are necessary to change the state of motion of an object.
  • Forces cause changes: When unbalanced forces are applied, they can change the shape, speed, or direction of an object.

---

[Physics]

Newton's First Law of Motion

Examples

• Objects at rest on a table remain stationary until an external force is applied.
• A moving car will continue to move forward unless brakes or another force are applied.

Summary