Newton's First Law of Motion (Law of Inertia) - JSS2 Basic technology Lesson Note

An object at rest will stay at rest, and an object in motion will stay in motion at a constant velocity, unless acted upon by a net external force.

This law implies that if no external force is applied to an object, its state of motion will not change. If it's at rest, it will remain at rest; if it's moving, it will continue moving in a straight line at constant speed.

Practical Examples:

• A book lying on a table remains at rest until someone moves it
• A hockey puck sliding on ice will keep moving in the same direction and speed unless friction or another force stops it.