physics

• what is a vector?

  a quantity which has size and direction (forces velocity momentum)
• what is scalar?

  a quantity which just has size (mass speed and time)
• how does a distance time graph show constant speed?

  straight line
• how does a distance time graph show a stationary object

  horizontal line
• how is acceleration calculated from a velocity time graph

  gradient of the line (steeper the line the greater the acceleration)
• what will happen to an object if the forces on it are balanced?

  it will continue moving with the same speed and direction (it will stay still if not already moving)
• what is the equation for weight

  mass x gravitational feild
• what does newton’s second law say about acceleration


  if the resultant force is bigger the acceleration is bigger. if the mass is bigger the acceleration is smaller
• what is the equation for newton’s second law?

  force= mass x acceleration
• what does newton’s third law say about the action and reaction forces on different objects?


  the forces will be the same size and will act in opposite directions
• what factors can increase thinking distance

  • higher speed

  • use of drugs

  • alcohols

  • distractions
• what factors can increase the breaking distance?

  •higher speed

  •worn tyres

  •wet or icy conditions

  •larger mass (more passengers)
• how is stopping distance calculated?

  thinking + breaking distance
• name two safety features which reduce the forces acting in a collision?

  air bags and crumple zones
• how do crumple zones reduce the forces acting in a collision

  they increase the time for the car to stop. this decreases the deceleration and so decreases the force
• what is centripetal force


  the resultant force which keeps an object moving in a circle
• what is the equations for momentum

  mass x velocity
• what is meant by conservation of momentum

  the total momentum of two objects before they collide equals their total momentum after they collide
• how are momentum and force connected

  force= momentum change / time
• how do you calculate the resultant force on an object?

  subtract the total force in one direction from the total force in the other direction
• do waves transfer matter energy or both?

  just energy
• what is the frequency of a wave?

  the number of waves in one second
• what is the period of a wave?


  the time taken for one complete wave to pass a point
• how is the period of a wave linked to its frequency?

  period = 1 / frequency
• what are the names of the two types of waves?

  transverse and longitudinal
• name three examples of transverse waves

  electromagnetic waves, water waves, s-waves
• name two types of longitudinal waves

  sound waves, p-waves
• how is heat energy transferred by convection?

  part of a fluid that is warmer than the rest rises and sets up a convection current
• how is heat energy transferred by radiation?

  it travels as infared an electromagnetic wave. this means that it can travel through a vacuum
• what sort of surfaces absorb and emit radiation well?

  dull dark surfaces
• what sort of surfaces absorb and emit radiation poorly?

  light shiny surfaces
• do insulators have a high or low thermal conductivity?

  they have low thermal conductivity
• what is the equation for gravitational potential energy?

  mass x gravitational field strength x change in height
• what is the equation for kinetic energy?


  1/2 x mass x (speed x speed)
• name four non renewable energy resources

  • coal
  • oil
  • natural gas
  • nuclear fuels (uranium)
• describe some problems with using non renewable resources

  • burning fossil fuels releases co2
  • nuclear waste can stay radioactive for millions of years
• name renewable energy resources

  • solar
  • wind
  • hydroelectricity
  • bio-fuels
• why cant we just use renewable sources to generate elctricity?

  most aren't available all the time (eg wind speeds need to be suitable) and a lot of land is needed to produce enough energy
• name the six ways in which energy can be stored in an object?

  • chemical
  • kinetic
  • thermal
  • elastic potential
  • gravitational potential energy
  • nuclear energy
• name the 4 ways in which energy can be transferred between objects

  • light energy
  • sound energy
  • electrical energy
  • thermal energy