Contact and non contact forces

• A force is a push or a pull that acts on an object due to the interaction with another object
• all forces are vector quantities ( have magnitude and direction
• What is the unit for force

  Newton (N)
• What is a contact force?

  . Occurs when two objects are physically touching
• examples of contact forces

  . Tension (e.g. in a rope)

  . Friction

  . Air resistance

  . Normal contact force
• What is an example of a normal contact force

  . A lamp on a table exerting a force downward (weight)

  . At the same time, the table is exerting an upwards force on the lamp (normal contact force)

  . This can only happen if two objects are in direct contact
• What is a non contact force?

  . The two objects are physically separated
• Examples of non contact forces

  . Gravitational force

  . Electrostatic force between two charged objects

  . Magnetic force