2.2 Forces and Free-Body Diagrams

• What is the SI unit of force?

  Newton
• Force is a scalar quantity.

  False
• Forces are represented using vectors
• Steps to construct a free-body diagram

  1️⃣ Isolate the object

  2️⃣ Identify all forces acting

  3️⃣ Draw force vectors

  4️⃣ Label each force
• The normal force is always perpendicular to the surface of contact.


  True
• Friction force opposes the relative motion between two surfaces
• Gravitational force is the attractive force between an object and the Earth
• What type of force opposes relative motion between two surfaces in contact?

  Friction force
• What is a free-body diagram used for?

  Analyzing forces
• The SI unit of force is defined as the force required to accelerate a mass of 1 kg at a rate of 1 m/s^2
• Match the quantity with its definition and SI unit:

  Force ↔️ Interaction between two objects ||| Newton (N)

  Mass ↔️ Amount of matter in an object ||| Kilogram (kg)

  Acceleration ↔️ Rate of change of velocity ||| Meter per second squared (m/s^2)
• What is gravitational force also known as?

  Weight
• Tension force is exerted by a rope, string, or cable.


  True
• Match the force type with its example:

  Gravitational Force ↔️ A ball falling to the ground

  Normal Force ↔️ A book resting on a table

  Friction Force ↔️ A car braking on the road
• What does the length of a force vector arrow indicate?

  Magnitude of the force
• Give an example of a scalar quantity.

  Mass
• Forces are represented by arrows in diagrams, where the arrowhead shows the direction
• What is the purpose of a free-body diagram?

  Analyze forces affecting motion
• In a free-body diagram, the length of a force vector is proportional to its magnitude.


  True
• What is the primary focus of a free-body diagram?

  Forces acting on an object
• A free-body diagram is a simplified visual representation of an object and the forces acting on it.

  True
• What two forces act on a box resting on a table?

  Gravitational and Normal
• What is the SI unit of force?

  Newton
• Gravitational force is the attractive force between an object and the Earth.


  True
• Friction is a force that opposes relative motion
• Match the vector property with its definition:

  Magnitude ↔️ Amount of force in Newtons

  Direction ↔️ Direction the force acts
• What is a scalar quantity characterized by magnitude only?

  Mass
• A vector quantity has both magnitude and direction
• What is a free-body diagram?

  Simplified visual representation of forces
• Steps to draw a free-body diagram

  1️⃣ Isolate the object

  2️⃣ Identify forces

  3️⃣ Draw vectors

  4️⃣ Label forces
• Match the force type with its description:

  Gravitational Force ↔️ Pulls objects towards Earth

  Normal Force ↔️ Surface force perpendicular to object

  Tension Force ↔️ Exerted by a rope or cable
• The gravitational force \( F_g \) pulls objects towards the Earth
• The length of force arrows in a free-body diagram represents their relative magnitudes.


  True
• The friction force \( F_f \) opposes the motion of an object.
• What are the two forces acting on a box suspended by a rope?

  Gravity and tension
• The gravitational force (F_g) pulls an object downwards
• Steps to draw a free-body diagram

  1️⃣ Isolate the object

  2️⃣ Identify forces

  3️⃣ Draw vectors

  4️⃣ Label forces
• In a free-body diagram, each force must be clearly labeled
• What is the SI unit of force?

  Newton
• The SI unit of mass is the kilogram