Energy Stores + Transfers Flashcards
what is a system
an object/group of objects
what are the factors affecting rate of heat loss from a building
-thickness of the walls and roofs
-thermal conductivity of the walls and roofs
-temperature difference between two sides of wall/roof
name 3 factors that determine rate of energy transfer through a material
-thermal conductivity of material
-temperature difference
-thickness of the material
which materials have low thermal conductivity
thermal insulators
name unit that represents 1 joule transferred per second
watt (w)
describe energy transfer of a ball fired suing an elastic band
energy transferred mechanically from elastic store of the band to kinetic of the ball - some energy dissipated of thermal store of the surroundings
describe energy transfer when electric kettle heats water
electric current in kettle transfers energy to thermal store - then transferred by heating to thermal store of the water
describe energy transfer when a moving car slows down
energy transferred mechanically from kinetic store of the car to the thermal store of brakes - some energy dissipated to the surroundings
what is one joule of work
work done when a force of 1N causes an object to move 1m in direction of force
what is work done
energy transferred when a force moves an object
what is a closed system
a system where no energy can be transferred to or from the surroundings - total energy always stays the same
4 ways energy can be transferred
-heating
-waves
-electric current
-mechanically (forces)
Name 8 energy stores
-kinetic
-gravitational potential
-elastic potential
-thermal
-chemical
-nuclear
-magnetic
-electrostatic
