We use forces to describe the interaction between two objects. The magnitude of the force that describes this interaction is the same on both objects. Newton proposed this statement, now known as Newton's third law, which can be stated as, "every action has an equal and opposite reaction
NASA video discusses the concept of Newtons's Third Law:
https://www.youtube.com/watch?v=cP0Bb3WXJ_k
Big Ideas
Big Idea 3: The interactions of an object with other objects can be described by forces.
Big Idea 4: Interactions between systems can result in changes in those systems.
Big Idea 5: Changes that occur as a result of interactions are constrained by conservation laws.
Learning Objectives
BoxSand Learning Objectives
- Demonstrate the ability to identify force pairs.
- Demonstrate the ability to differentiate between equal and opposite forces, such as the tension at the ends of a rope, and force pairs, such as the normal force between a box and the ground that it lies on.
- Understand that force pairs are equal in magnitude, no matter how large the mass difference is between the two interacting objects.
- Understand that the third law is an empirical law, along with the second law, which further illustrates that a force is the description of an interaction between two objects.
College Board Learning Objectives
Enduring Understanding and Essential Knowledge
|
Enduring Understanding |
Essential Knowledge |
Assumptions
Describe what the assumptions are and why they're important
 |
 |
History
Physics Fun
In the gif below, the force the gun puts on the bullets is equal and opposite to the force the bullets put back on the gun.
 |