[2.2] Forces

• FORCE


  Describes the interaction between two objects that can change the motion of one or both of them.
• UNBALANCED FORCES


  The force applied in one direction is greater than the force applied in the opposite direction.
• POSSIBLE OUTCOMES OF UNBALANCED FORCES

  1. An object may start moving.
  2. A moving object could be stopped.
  3. An object’s direction and speed can be changed.
• BALANCED FORCES


  Forces that are equal in magnitude but opposite in direction.
• CONTACT FORCES


  When two objects make physical contact and interact.
• APPLIED FORCE


  Force (push or pull) that is applied to an object by a person or another object.
• NORMAL FORCE


  Support force that surfaces exerts on an object. Always perpendicular to the contacting surface.
• FRICTIONAL FORCE


  Opposing force. Acts opposite to the direction of motion of an object.
• AIR RESISTANCE


  Acts upon objects as they travel through the air.
• TENSIONAL FORCE


  Transmitted through a string, rope, cable, or wire when it is being pulled by forces acting from opposite ends.
• SPRING FORCE


  Force exerted by a compressed or stretched spring upon any object that is attached to it.
• NON-CONTACT FORCES


  Do not require or involve any physical contact between two objects.
• GRAVITATIONAL FORCE


  The downward force exerted on an object that is equal to its weight. Exists between all bodies that have mass.
• MAGNETIC FORCE


  Responsible for the attraction of magnetic materials by the force of magnets.
• ELECTROSTATIC FORCE


  Acts between two charged bodies, “Opposite charges attract, like charges repel.”
• STRONG NUCLEAR FORCE


  The force between protons and neurons that keeps the nucleus together.
• WEAK NUCLEAR FORCE


  Responsible for the radioactive decay of certain nuclei.
• NET FORCE


  The sum of all the forces acting on an object.