4.1.1 Energy Changes In A System And The Ways Energy Is Stored Before And After Such Changes Flashcards
What is a system?
A system is an object or a group of objects
What is the equation for kinetic energy?
0.5xmass x velocity squared
What is kinetic energy measured in ?
Joules ( J )
What is mass measured in?
Kilograms (kg)
What is velocity measured in?
Metres per second (m/s)
What is the equation for elastic potential energy?
0.5 x spring constant x extension squared
What is elastic potential energy measured in?
Joules ( J )
What is spring constant measured in?
Newtons per metre ( N/m )
What is extension measured in ?
Metres ( m )
What is the equation for gravitational potential energy?
Mass x gravitational field strength x height
What is gravitational potential energy measured in?
Joules ( J )
What is gravitational field strength measured in?
Newtons per kilogram ( N/kg )
What is height measured in?
Metres ( m )
What is the equation for specific heat capacity?
Change in thermal energy = mass x specific heat capacity x change in temperature
What is change in thermal energy measured in ?
Joules ( J )
What is specific heat capacity measured in ?
Joules per kilogram per degrees Celsius ( J/kg degrees celsius
What is temperature change measured in?
Degrees celsius
What is specific heat capacity?
The amount of energy required to raise the temperature of one kilogram of the substance by one degrees Celsius
What is elastic potential energy?
The energy stored in an elastic object when work is done in the object
What is kinetic energy?
The energy stored in a moving object when work is done on the object
What is gravitational potential energy.
The energy stored in an object that is above the ground when work is done
What is power?
The rate at which energy is transferred or the rate at which work is done
What is the equation for power?
Energy transferred / time
What does work equal?
Energy transferred
What is power measured in?
Watts ( W )
What is work / energy transferred measured in ?
Joules ( J )
What is an energy transfer of 1 joule per second equal to?
A power of 1 watt
What is the conservation of energy?
Energy can be transferred usually stored or dissipated but cannot created or destroyed
What is the term wasted energy used for ?
Energy that isn’t used usefully
What does the higher the thermal conductivity equal?
The higher the thermal conductivity of a material the higher the rate of energy transfer by conduction across the material
What is the equation of efficiency?
Useful output energy transfer/ total input energy transfer
What is another equation for efficiency?
Useful power output / total power input
What are the main energy resources available for use on earth?
Fossil fuel , nuclear fuel , bio fuel , wind , hydroelectricity, geothermal, the tides , the sun and water waves
What is a renewable energy source ?
A source that is being or can be replenished as it is used
What are some uses of energy resources?
Transport, electricity generation and heating
What is spring constant?
a measure of the stiffness of the spring
