Newton's First Law of Motion (Law of Inertia):
* An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.
Key Concepts:
* Unbalanced Force: For an object to accelerate, there must be a net force acting on it. This means the forces acting on the object are not equal and opposite.
* Balanced Forces: If the forces acting on an object are balanced, they cancel each other out. This results in a net force of zero, and the object will not accelerate.
Examples:
1. A Book on a Table: A book resting on a table experiences the force of gravity pulling it downwards and the normal force from the table pushing it upwards. These forces are equal and opposite, resulting in zero net force. The book remains stationary.
2. A Person Pushing a Wall: A person pushing a wall exerts a force, but the wall pushes back with an equal and opposite force. The forces are balanced, and neither the person nor the wall accelerates.
3. An Object in Freefall (Ignoring Air Resistance): An object in freefall experiences only the force of gravity. However, because there's no opposing force, the object accelerates downward due to the unbalanced force.
Conclusion:
A body can have forces applied on it but not accelerate if those forces are balanced. The net force acting on the body is zero, so it remains at rest or continues to move at a constant velocity.
