Physics - Mechanics 1

• What is the definition of a vector quantity?


  A vector has both magnitude and direction
• What is the definition of a scalar quantity?


  A scalar only has magnitude
• What are examples of vector and scalar quantities?

  • Vector quantities:
  • Displacement
  • Velocity
  • Acceleration
  • Force
  • Scalar quantities:
  • Speed
  • Mass
  • Time
  • Energy
  • Power
• How does a vector differ from a scalar?


  A vector has both magnitude and direction, while a scalar has only magnitude
• What is equilibrium in physics?


  An object is in equilibrium if all forces acting on it cancel out and the principle of moments applies.
• What defines a moment in physics?


  A moment is the turning effect of a force, calculated as force times the perpendicular distance from the point to the line of action of the force.
• What does the principle of moments state?


  The sum of clockwise moments equals the sum of anticlockwise moments about a point for a system in equilibrium.
• What is the centre of mass of an object?


  The centre of mass is the point where all mass of an object can be thought to be concentrated.
• What is a couple in physics?


  A couple is a pair of equal and opposite coplanar forces.
• How is the moment of a couple calculated?


  The moment of a couple is calculated as force times the perpendicular distance between the lines of action of the forces.
• What is a free body force diagram?


  A free body force diagram is a diagram of an object showing only the forces acting on it.
• What is a resultant vector?


  A resultant vector is the vector formed when two or more vectors are added together.