Physics GCSE Unit 1: Energy Flashcards
What is a system?
A system is an object or group of objects that interact.
What happens when a system changes?
When a system changes, the way energy is stored also changes.
What are the eight energy stores?
Kinetic
Thermal
Chemical
Elastic potential
Gravitational potential
Electrostatic
Magnetic
Nuclear.
What objects store kinetic energy?
Moving objects store kinetic energy.
What objects store thermal energy?
All objects store thermal energy.
What objects store chemical energy?
Any object that can release energy during a chemical reaction.
What objects store elastic potential energy?
Any object that is stretched.
What objects contain gravitation potential energy?
Any object that is raised.
What objects contain electrostatic energy?
Any object with charges that attract or repel.
What objects contain magnetic energy?
Magnets that attract or repel.
What are the four methods of energy transfer?
Mechanical (when work is done)
Electrical (when moving charges do work)
Heating (Energy transferring from a hotter object to a colder object0
Waves (such as light or infra-red)
What is the equation for thermal energy?
Energy (J) = mass (kg) x specific heat capacity (j/kgdegC) x Temperature Change (degC)
Define Specific Heat Capacity.
Specific Heat Capacity is the energy required to raise the temperature of 1kg of a substance by 1degC.
What is the equation for Elastic Potential Energy?
Elastic potential energy (J) = 1/2 x spring constant (n/kg) x extension (m2).
What is the equation for Kinetic Energy?
Kinetic energy (J) = 1/2 x mass (kg) x velocity2 (m/s)
What is the equation for Gravitational Potential Energy?
GPE (J) = mass (kg) x gravitational field strength (n/kg) x height (m).
What is work done?
Work done is the amount of energy transferred.
What is power?
Power is the rate of energy transfer (the amount of work done in a period of time).
What is the equation for power?
Power (W) = Energy transferred (j) / Time taken (s) = Work done (J)) / Time taken (s)
What is the equation for Efficiency?
Efficiency = Useful Energy Output / Total Energy Input
How can the efficiency of a system be increased?
Reducing waste output (thermal insulation)
Recycling waste output
How does lubrication reduce energy waste?
Lubrication reduces friction so less energy is lost as heat.
What does thermal insulation do?
Thermal insulation prevents the loss of more thermal energy.
Why are metals good conductors?
Metals are good conductors as they have delocalised electrons that can more easily transfer heat.
