FINAL REVISION: Physics Term 1

• What is potential energy? This is stored energy. Such as

  Gravitational potential energy (objects with

  mass at a height)

  Elastic Potential Energy (e.g., energy stored

  in a spring)

  Chemical Potential energy (energy stored in

  chemicals e.g., food, battery, petrol)

  Nuclear Potential

  Magnetic Potential
• What is active energy? This is energy that is not stored that causes

  movement (of waves or particles)

  e.g., Kinetic energy,

  Light energy, Electrical,

  Heat, Sound
• What are these types of energy?

  
  

  Petrol in a car - is…… Chemical potential

  energy.

  Person running is … Kinetic energy

  Stretched rubber band is Elastic potential

  energy.

  Burning match is heat energy (and some

  light energy)

  Skydiver standing on a building =

  Gravitational potential energy
• Energy can be transformed from one type to

  another.

  When a battery is used to turn on a light bulb,

  describe the energy transformations.

  Chemical potential energy(battery)

  to electricity to Light and heat (lightbulb)
• When a skateboarder is standing on the top of

  a hill and lets the skateboard move down it.

  Describe the energy transformation.

  Gravitational potential energy (top of hill)

  to Kinetic energy (moving) to heat and sound

  (comes to a halt at bottom)
• Explain what the law of Conservation of energy

  means?

  The input energy must be the same as the

  output energy.

  It means when energy is transferred or

  transformed, new energy is not created, nor

  is energy destroyed.
• A light bulb uses 1500 joules energy to operate.

  400 joules of energy is used for light every

  minute.

  How much wasted energy is there and where

  does it go?

  1500 – 400 =1100 joules of wasted energy

  The wasted energy is heat energy.
• State the law of conservation of energy: Energy cannot be created or destroyed, it can only be transferred or transformed.
• What is renewable energy?

  Renewable energy is defined as energy that is collected from resources that will never run out or which are replaced by nature in less than a human lifetime.
• What is non-renewable energy?

  Non-renewable energy is defined as energy collected from resources that cannot be replaced when they are used up, such as oil, natural gas, or coal.
• Examples of renewable and non-renewable energy sources in New Zealand?

  Renewable: Hydroelectric energy, solar power, wind turbines, geothermal energy, biofuel energy.

  Non-renewable: Fossil fuel, nuclear energy, natural gas, coal.
• Pros and Cons of hydroelectric power generation?

  Cons: Damage to the estuary habitats and damage to valley habitats by flooding.

  Pros: Cheap to run (no fuel costs) and no polluting gasses produced.
• What is energy efficiency?

  How much of the input energy is transformed to a useful form. Represented as a %.
• What is the unit for energy?

     Joules  

    1000 joules = 1 kilojoule (kJ)
• Energy efficiency %=(useful energy/ input energy) x100
• Gravitational Potential Formula:

  Ep = m g h (g = 10 ms^-1)
• Kinetic Energy Formula:

  Ek = 1/2 m v^2