energy

• • In physics, work done is the energy transferred when a force is used to move an object a certain distance
• • Work done = Force x Distance moved (J)
• • The unit of work done is joules (J) or newton metres (Nm).
• • Energy can be stored as potential energy.
• • Potential energy is the ability to do work due to its position or condition.
• Work can be done in a a range of situations e.g. lifting a book work is done against gravity, when you slide a book

  along a table work is done against friction
• work done (J) = force (N) × distance moved (m)
• A simple machine makes it easier to lift things, they reduce the force needed
• A force multiplier uses a smaller input force (what you apply) to to generate a larger output force (what is created)
• If you increase the distance from the pivot, less input force is needed to be used for the same output force as before
• A lever is an example of a force multiplier, a longer lever will require a less input force than a shorter lever to produce

  the same output force
• efficiency= useful power out/total power in x100
• the 8 energy stores?

  Chemical, thermal, kinetic, gravitational potential, elastic potential, nuclear, electrostatic, magnetic.
• the 4 heat transfers?

  waves,mechanical,heating,electric currents
• work is the same as power
• wasted thermal energy tends to be sound waves
• atomic/ nuclear energy= when it is stored inside atoms
• chemical energy= stored in chemical substances
• dissipated= spread out
• efficiency= proportion of energy transferred to a useful form
• Energy: something that is needed to make things happen or change.
• joules (J): a unit for measuring energy.
• Kinetic energy: a term used to describe energy when it is stored in moving

  things.
• Law of conservation of energy: the idea that energy can never be created or

  destroyed, only transferred from one form to another.
• Power: the amount (rate) of energy transferred per second. The units are

  watts (W).
• System: a set of things being studied. For example, a kettle, the water in it

  and its surroundings form a simple system.
• Thermal energy: a term used to describe energy when it is stored in hot

  objects. The hotter something is, the more thermal energy it has. Sometimes

  called ‘heat energy’.
• Useful energy: energy transferred to where it is wanted in the way that is

  wanted.
• Wasted energy: energy that is not usefully transferred.
• watts (W): the unit for measuring power. 1 watt = 1 joule of energy

  transferred every second.
• Work: the energy transferred by a force. Work done (joules, J) = force

  (newtons, N) x distance moved in the direction of the force (metres, m).
• Work done: a measure of the energy transferred when a force acts through

  a distance.
• Describe the energy transfers that happen when an object falls.
• Describe the energy transfers that happen when a falling object hits the

  ground without bouncing back.
• Conserving energy is key to reducing our reliance on nonrenewable resources, 
• A closed system is a natural physical system that does not allow transfer of matter in or out of the system, 
• A closed system is an isolated system in which no energy transfers take place out of or into the energy stores of the system. Energy can be transferred between energy stores within a closed system
• Write down which materials make the best conductors.
• Write down which materials make the best insulators.
• Describe how the thermal conductivity of a material affects the rate of

  energy transfer through it by conduction