**Newton’s First Law of Motion (Law of Inertia):**
Newton’s First Law states th

**Newton’s First Law of Motion (Law of Inertia):**
Newton’s First Law states that:
*”An object at rest will remain at rest, and an object in motion will continue moving at a constant velocity in a straight line, unless acted upon by an external force.”*
### Key Points:
1. **Inertia**: This property is called inertia, which is the tendency of an object to resist changes in its state of motion. A body will not change its speed or direction unless an external force acts on it.
2. **Rest and Motion**:
– If an object is at rest, it will stay at rest unless a force pushes or pulls it.
– If an object is moving, it will continue moving at the same speed and in the same direction unless a force (like friction or another external influence) changes its state.
3. **Example**:
Imagine a book on a table. The book remains at rest because no external force is acting to move it. However, if you push the book, you apply an external force, causing it to move.
### Real-World Application:
– **Car and Seatbelt**: When a car suddenly stops, passengers who aren’t wearing seatbelts will continue moving forward due to inertia, potentially leading to injury. Seatbelts apply the necessary force to stop the passengers from continuing their motion.
In summary, the first law emphasizes that motion (or lack thereof) does not change without a force causing that change.