contact and non contact forces

• Force


  A push or pull that acts on an object due to the interaction with another object
• Forces have both magnitude (size) and direction
• The unit of force is the Newton
• Types of forces


  • Contact forces
  • Non-contact forces
• Contact forces


  • The two objects are physically touching
• Tension


  A contact force that pulls on an object, e.g. in a tug-of-war
• Friction


  A contact force that acts between two surfaces, e.g. an airplane landing on water
• Air resistance


  A contact force that acts on a falling object, e.g. a skydiver
• Normal contact force


  An upward force exerted by a surface on an object resting on it, e.g. a table supporting a lump
• Non-contact forces


  • The two objects are physically separated
• Gravitational force


  An attractive force between all objects, e.g. the Earth and the International Space Station
• Electrostatic force


  A force between charged objects, either attractive or repulsive
• Magnetic force


  A force experienced by certain objects in a magnetic field