1. Contact vs. Non-Contact
Forces
Contact vs. Non-Contact

2. Contact vs. Non-Contact Forces
Forces are responsible for all the intereactions between particles and objects.
Forces can be divided in 2 categories: contact; and non-contact.
Contact forces are forces that act between two objects that are physically touching each other.
Non-contact are forces that act between two objects that are not physically touching each other.

3. Forces
Contact
Non-contact
Reaction;
Tension;
Friction;
Air resistance.
Magnetic;
Electrostatic;
Gravitational

4. For every action, there is na equal and opposite reaction
Contact Force
When a contact force acts between two objects, both objects experience the same size force, but in opposite directions
Newton’s Third Law of Motion:
For every action, there is na equal and opposite reaction

5. Contact: Reaction Force
An object at rest on a surface experiences a reaction force.
Is a force acting in the opposite direction.

6. Contact: Tension Force
An object that is being stretched experiences a tension force.
Is the force that is transmitted through a string, rope, cable or wire when it is pulled by forces acting from opposite ends.

7. Contact: Friction Force
Two objects sliding past each other experience friction forces;
Friction: the resistance that one surface or object encounters when moving over another.
Depends on the materials

8. Contact: Air resistance Force
An object moving through the air experiences air resistance.
Is the frictional force air exerts against a moving object.
The faster the object’s motion, the greater the air resistance

9. Non-contact: Magnetic Force
A magnetic force is experience by any magnetic material in a magnetic field;
Magnetic field: área surrounding a magnet that can exert a force on magnetic materials.
Opposite poles atract each other.
Same poles repel each other

10. Non-contact: Electrostatic Forces
Is a force experienced by any charged particle in na electric field

11. Non-contact: Gravitational Force
Is a force experienced by any mass in a gravitational field.
Masses are attracted towards each other by gravitational force