energy transfers , heat transfers Flashcards
what are the 4 energy transfers?
mechanical, electrical, heat, radiation
gravitational potential energy
Object above the ground
Kinetic energy
in moving objects
magnetic
when 2 magnets attract or repel
elastic potential
in anything stretched
chemical
anything with energy that can be released by chemical reaction
thermal
everything has something from this store, hotter = more energy
electrostatic
when 2 electrical charges attract or repel
conservation of energy
energy can’t be created or destroyed only transferred
what are the units of energy?
Joules
equation for kintetic energy (with units)
0.5 x mass x velocity²
J= 0.5 x kg x m/s
equation for GPE
GPE = mass x gravitational field strength x height
J= kg x N/kg x m
what happens to hot and cool air ? (related to density)
hot air rises, cool air sinks
conductor
transfers energy easily (metals)
insulator
doesn’t transfer energy easily (plastic)
conduction
when heated particles gain kinetic energy, particles vibrate and pass internal energy to nearby particles causing them to vibrate more
convection
happens in liquid + gases, takes place of particles with less thermal energy
radiation
no particles involved, can happen when objects aren’t touching
all objects transfer energy to surroundings by infrared radiation
