- Slides: 11
Forces Contact vs. Non-Contact
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.
Forces Contact • • Reaction; Tension; Friction; Air resistance. Non-contact • Magnetic; • Electrostatic; • Gravitational
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
Contact: Reaction Force • An object at rest on a surface experiences a reaction force. • Is a force acting in the opposite direction.
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.
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
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
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
Non-contact: Electrostatic Forces • Is a force experienced by any charged particle in na electric field
Non-contact: Gravitational Force • Is a force experienced by any mass in a gravitational field. • Masses are attracted towards each other by gravitational force