energy Flashcards
(29 cards)
What energy stores are there?
magnetic, thermal, chemical, kinetic, electrostatic, elastic potential, gravitational potential, nuclear.
What is work done?
energy has been transferred.
What is dissipation?
the spreading out and transfer of energy into less useful forms, ‘wasted’ energy.
What are the energy transfers?
mechanical, electrical, heating and radiation.
Calculation for kinetic energy.
1/2 mass x speed^2= Ek= 1/2 mv^2
Calculation for elastic potential energy.
1/2 x spring constant x extension^2= Ee= 1/2 Ke^2
Calculation for gravitational potential energy.
mass x gravitational field strength x height = Ep= mgh
Calculation for work done.
force x distance= W= f x d
Calculation for power.
work done/ time= p= w/t
What is efficiency?
The fraction of energy supplied to a device which is transferred into a useful form.
Calculation for efficiency.
useful energy transferred/ total energy supplied
Define insulator
material that does not allow charge or energy to pass.
What is specific heat capacity?
the amount of energy needed to raise temperature of 1kg of a substance to 1*c
Calculation for change in thermal energy.
mass x specific heat capacity x temperature change= ΔEt= m x c x Δθ
Calculation of kinetic energy of a moving object.
Kinetic energy = 0.5 mass x (speed) squared.
Calculation of gravitational potential energy of a raised object.
gravitational potential energy = mass x gravitational field strength x height.
Calculation of elastic potential energy of a spring.
elastic potential energy = 0.5 x spring constant x (extension) squared.
Calculation of the thermal energy put into/ given out a system when its temperature changes.
change in thermal energy = mass x specific heat capacity x temperature changes
Calculation of power in a system.
power = work done / time OR power = energy transferred / time.
What is the (1)energy store, (2)renewable/ non renewable, (3)main uses, (4)reliability and (5)environmental impact of fossil fuels.
(1) chemical
(2) non-renewable
(3) transport, heating, generating electricity
(4) very reliable
(5) releases carbon dioxide, responsible for global warming.
What is the (1)energy store, (2)renewable/ non renewable, (3)main uses, (4)reliability and (5)environmental impact of nuclear fuel (mainly uranium)
(1) nuclear
(2) non-renewable
(3) generating electricity
(4) very reliable
(5) makes dangerous radioactive waste that needs to be buried for many years
What is the (1)energy store, (2)renewable/ non renewable, (3)main uses, (4)reliability and (5)environmental impact of biofuel.
(1) chemical
(2) renewable
(3) transport, heating, generating electricity
(4) very reliable
(5) low negative impact, carbon neutral.
What is the (1)energy store, (2)renewable/ non renewable, (3)main uses, (4)reliability and (5)environmental impact of wind.
(1) kinetic
(2) renewable
(3) generating electricity
(4) unreliable, weather dependent
(5) take up big areas of land, birds could be killed, does not emit anything.
What is the (1)energy store, (2)renewable/ non renewable, (3)main uses, (4)reliability and (5)environmental impact of hydroelectricity.
(1) gravitational potential
(2) renewable
(3) generating electricity
(4) very reliable
(5) big areas need to be flooded to create dams
