physics 2

• Scalar quantities


  Quantities that have magnitude only
• Vector quantities


  Quantities that have magnitude and an associated direction
• Vector quantities


  • Forces
• Contact forces


  • Objects are physically touching
• Non-contact forces


  • Objects are physically separated
• Contact forces


  • Friction, air resistance, tension, normal contact force
• Non-contact forces


  • Gravitational force, electrostatic force, magnetic force
• Resolving forces


  Replacing a number of forces acting on an object with a single force that has the same effect
• Demand curve shifting right

  Increases the equilibrium price and quantity
• Marginal utility


  The additional utility (satisfaction) gained from the consumption of an additional product
• If you add up marginal utility for each unit you get total utility
• Weight


  The force acting on an object due to gravity
• Gravitational field strength


  The force of gravity close to the Earth
• Weight and mass are directly proportional
• Work done


  When a force causes an object to move through a distance
• Joule


  Unit of work done when a force of one Newton causes a displacement of one metre
• Work done against frictional forces causes a rise in the temperature of the object
• Elastic deformation


  Deformation that is reversible
• Plastic deformation


  Deformation that is not reversible
• Limit of proportionality


  The point at which the spring stops obeying Hooke's Law
• Distance


  How far an object moves (scalar quantity)
• Displacement


  Distance an object moves in a straight line from start to finish, including direction (vector quantity)
• Speed


  Rate of change of position (scalar quantity)
• Velocity


  Speed in a given direction (vector quantity)
• Acceleration


  Rate of change of velocity
• Terminal velocity


  The constant velocity reached by an object falling through a fluid when the resultant force is zero
• Static electricity


  Charge generated by rubbing certain insulating materials together
• Electric field


  The region around a charged object where a force would be experienced by another charged object
• The electric field is strongest close to the charged object and gets weaker with distance
• The force between two charged objects gets stronger as the distance between them decreases
• An electric field can cause sparking
• Electric field


  Field around a charged object
• The electric field is strongest close to the charged object


  The further away from the charged object, the weaker the field
• A second charged object placed in the field

  Experiences a force
• The force gets stronger


  As the distance between the objects decreases
• Electric field


  Can be used to explain the non-contact force between charged objects and other electrostatic phenomena such as sparking
• The strength of an electric field

  Varies with distance from the charged object
• Two charged objects in close proximity

  Exert a force on each other
• The size of the force


  Varies with the distance between the charged objects
• This is A-level topic but it's a useful resource with good links: