5.1.2 Contact and Non-Contact Forces

• What are contact forces defined as?

  Forces between touching objects
• Contact forces arise from the interaction between the surfaces
• Arrange the following contact forces in order of their appearance in the example scenarios:

  1️⃣ Friction (shoe on the ground)

  2️⃣ Tension (tightrope)

  3️⃣ Normal force (book on a table)
• Tension is a contact force exerted by a string, rope, or cable
• The normal force is always exerted perpendicular to the surface of an object.


  True
• Non-contact forces act through fields of influence, such as gravitational, magnetic, and electric
• Non-contact forces require objects to be physically touching each other.

  False
• What is the gravitational force?

  Attraction between objects with mass
• What is the electric force?

  Attraction or repulsion between charged objects
• Contact forces only exist when objects are in direct physical contact.


  True
• Match the contact force with its example:

  Friction ↔️ Shoe on the ground

  Tension ↔️ Tightrope

  Normal force ↔️ Book on a table
• What is the role of friction as a contact force?

  Opposes relative motion
• What are non-contact forces defined as?

  Forces between non-touching objects
• Match the non-contact force with its example:

  Gravitational force ↔️ Earth and object

  Magnetic force ↔️ Magnet and iron

  Electric force ↔️ Positively and negatively charged objects
• Arrange the following non-contact forces in order of their appearance in the examples:

  1️⃣ Gravitational force (Earth and object)

  2️⃣ Magnetic force (magnet and iron)

  3️⃣ Electric force (charged objects)
• The magnetic force is a force of attraction or repulsion between magnetic objects
• Non-contact forces require physical contact to act.

  False
• The gravitational force is an example of a non-contact force
• Give an example of magnetic force in action.

  Two magnets attracting
• Match the contact force with its description:

  Friction ↔️ The force that opposes motion between surfaces

  Tension ↔️ The force in a rope or cable when pulled taut

  Normal Force ↔️ The force exerted perpendicular to a surface
• Tension is the force exerted by a string, rope, or cable when it is pulled taut
• What is the normal force?

  Force perpendicular to a surface
• What is an example of tension in real life?

  A tightrope
• Match the non-contact force with its real-life application:

  Gravitational Force ↔️ Keeps planets orbiting the Sun

  Magnetic Force ↔️ Allows compasses to point north

  Electric Force ↔️ Causes static electricity to discharge
• What are non-contact forces?

  Forces acting without physical touch
• Match the non-contact force with its description:

  Gravitational Force ↔️ Force of attraction between objects with mass

  Magnetic Force ↔️ Force of attraction or repulsion between magnetic objects

  Electric Force ↔️ Force of attraction or repulsion between charged objects
• Contact forces arise from the interaction between surfaces
• What is friction?

  The force that opposes motion
• Contact forces require physical touch, while non-contact forces do not.


  True
• The force between car tires and the road is an example of friction
• The gravitational force keeps planets in orbit
• What does the magnetic force allow compasses to do?

  Point towards magnetic north