Chap 3 - energy, work done, power Flashcards
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 = 9.8Nm^-1
h = meters
define law of conservation of energy
-energy cannot be created or destroyed
-energy is converted to other forms
-total energy is constant
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
define power
how much 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 energy/ power / total energy/power x 100%
-100% is usually put with denominator
what diagram is use to show efficiency
sankey diagram
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 is nuclear fission
nuclei of atoms are split apart
how are fossil fuels used
burned to produce energy
how is nuclear fission of uranium used
the atom is split and releases energy in form of heat and radiation
how are wind resources used
get energy from wind using mechanical power to spin a generator
how are hydroelectric dams used
converts GPE in water in reservoir into KE to turn the turbine