Contents
Key Stage 4
Meaning
Newton's First Law states that "An object in motion will tend to stay in motion in a straight line and an object at rest will tend to stay at rest unless an unbalanced force acts upon it."
About Newton's First Law
- Newton's First Law describes the fact that:
- If the resultant force on an object is zero then it will continue to move at a constant velocity.
- If the resultant force on an object is not zero then an object will accelerate (change speed or direction).
- This means that if an object is observed changing speed or direction then there must be an unbalanced force acting on it.
Examples
Stationary Object - The object remains at rest because the forces and balanced.
Uniform Velocity - The object remains at a constant speed and continues in a straight line because the forces acting on the object are balanced.
Uniform Speed but Changing Velocity - The object is changing direction because there are unbalanced forces acting on it.
Changing Speed - The object is changing speed because there are unbalanced forces acting on it.