Forces & their Interactions

• What is a scalar quantity?

  A quantity that only has a magnitude
• Why is a scalar quantity not direction dependent?

  Because it only represents magnitude without any directional component
• What is a vector quantity?

  A quantity that has both a magnitude and an associated direction
• How can a vector quantity be visually represented?

  As an arrow
• What does the length of a vector arrow represent?

  The magnitude of the vector quantity
• What does the direction of a vector arrow indicate?

  The associated direction of the vector quantity
• What is a force?

  A push or pull acting on an object due to an interaction with another object
• What are the two categories that all forces can be split into?

  Contact forces and non-contact forces
• What are examples of contact forces?


  • Friction
  • Air resistance
  • Tension
• What are examples of non-contact forces?

  • Gravitational forces
  • Electrostatic forces
  • Magnetic forces
• Is force a vector or a scalar quantity?

  Force is a vector quantity
• Give three examples of vector quantities.

  • Velocity
  • Displacement
  • Force
• Give three examples of scalar quantities.

  • Temperature
  • Time
  • Mass
  • Speed
  • Distance
  • Energy
• What is weight?

  The force that acts on an object due to gravity and the object’s mass
• What quantities does weight depend on?

  Weight depends on the object's mass and the gravitational field strength
• What is the formula for weight?

  Weight = mass x gravitational field strength
• What is the unit used for weight?

  The Newton (N)
• What is the unit used for gravitational field strength?

  N/kg
• What is meant by an object’s centre of mass?


  The single point where an object’s weight can be considered to act through
• What piece of equipment can be used to measure an object’s weight?

  A calibrated spring-balance or newton-meter
• What is the name given to the single force that is equivalent to all the other forces acting on a given object?

  The resultant force