.2 Contact and non-contact forces

• A force is a push or pull that acts on an object due to the interaction with another object. All forces between objects are either: 


  contact forces – the objects are physically touching

  non-contact forces – the objects are physically separated.
• Examples of contact forces include friction, air resistance, tension and normal contact force
• Examples of non-contact forces are gravitational force, electrostatic force and magnetic force.
• Force is a vector quantity.