Newton's Third Law: Action and Reaction
* Equal in magnitude: Newton's Third Law states that for every action, there is an equal and opposite reaction. This means the forces in a pair are always equal in magnitude.
* Opposite in direction: The forces in a pair always act in opposite directions.
Forces Acting on Cardboard at Rest
When the cardboard box is at rest, it means the net force acting on it is zero. Here's a breakdown of the forces involved:
1. Weight (Force of Gravity): The Earth exerts a downward force on the cardboard due to gravity. This force is called the weight of the cardboard.
2. Normal Force: The surface the cardboard rests on exerts an upward force on the cardboard. This force is called the normal force and is equal in magnitude but opposite in direction to the weight.
Example
Imagine a cardboard box sitting on a table.
* Weight (Action): The Earth pulls the cardboard down with a force of, say, 10 Newtons.
* Normal Force (Reaction): The table pushes the cardboard upwards with a force of 10 Newtons.
Summary
When the cardboard is at rest, the forces acting on it are:
* Weight: Downwards
* Normal Force: Upwards
These forces are:
* Equal in magnitude: The weight and the normal force are equal in strength.
* Opposite in direction: The weight acts downwards, and the normal force acts upwards.
This balance of forces is what keeps the cardboard at rest.
