When an object applies a force on another object, the second object applies a force of the same strength on the first object, but the force is in the opposite direction.
Newton's Third Law of Motion
Force Pairs
A force pair is the forces two objects apply to each other.
Action and Reaction
In a force pair, one force is called the action force. The other force is called the reaction force.
For every action force, there is a reaction force that is equal in strength but opposite in direction.
Using Newton's Third Law of Motion
When the reaction force results in an unbalanced force, there is a net force, and the object accelerates.
Momentum
A measure of how it is to stop a moving object.
Momentum means "movement, impulse."
Object's momentum is in the same direction as its velocity.
More mass = more momentum.
Conservation of Momentum
Law of Conservation
In any collision, one object transfers momentum to another object.
The total momentum of a group of objects stays the same unless outside forces act on the objects.
Types of Collisions
Elastic collision happens when objects bounce off each other.
Inelastic collision happens when objects collide and stick together.
