P1 - motion, forces, energy (energy, work done, power) Flashcards
(41 cards)
law of energy conservation
-energy cannot be created or destroyed, only transferred
-total energy is constant
name the 9 energy types
-thermal
-chemical
-nuclear
-light
-electricity
-kinetic
-sound
-gravitational potential
-elastic potential
unit for energy
joules ( J )
4 ways of energy transfer
-mechanical work done
-electrical work done
-heating
-wave
explain mechanical work done energy transfer
an applied force
explain electrical work done energy transfer
difference in charge causing electrical charges to move
explain heating energy transfer
due to difference in temperature
explain wave energy transfer
wave is transferred as radiation
word, symbol and units of KE equation
kinetic energy = 1/2 x mass x velocity^2
KE = 1/2mv^2
KE = J
m = Kg
v = ms^-1
word, symbol and units of GPE equation
Gravitational potential energy = mass x gravitational field strength x change in height
GPE = mgh
GPE = J
m = Kg
g = 9.8Nkg^-1
h = meters
definition of work done
transferring energy by mechanical or electrical pathways
word, symbol and units of work done equation
work done = force x distance
w = Fd
w = J
F = N
d = meter
-work out the direction of the force before finding which distance to use
define power
energy / work done per unit time
word, symbol and units of power equation
power = useful energy / time
power = useful work done/ time
P = E/w / t
P = E (energy)/ w(work done)
t = seconds
word equation of efficiency
efficiency = useful output/ total input x 100%
-no units
-uses for energy/ power
what diagram is use to show efficiency
sankey diagram
define non-renewable source of energy
energy that is being used faster than it is made (unsustainable)
define renewable source of energy
energy that is made faster than used
name 4 non renewable sources of energy
-fossil fuel - coal, oil, gas
-nuclear fission- uranium
name 9 renewable sources of energy
-wind
-hydroelectric dams
-tidal
-wave
-solar - solar cells, solar thermal collectors
-biofuel
-geothermal
what does the sun do
-radiates energy
-source of energy for except nuclear, tidal, geothermal
where is nuclear energy from (uranium)
earth’s core
where is geothermal energy from
earth’s core
how are fossil fuels used & energy transfer
-burned to produce energy
-chemical, thermal, kinetic, electrical