energy and forces - complete Flashcards
what are the energy laws?
-energy can not be created nor destroyed ( the law of conservation )
-energy tends to spread out and become less useful (eg hot objects always eventually cool down)
what is ‘power’
it is a measure on how fast energy is being transferred
what are the units of power?
(W) watts
(kW) kilowatts
what are the different types of energy stores
-chemical
-kinetic
-gravitational potential
-elastic potential
-magnetic
-electrostatic
-internal (or thermal)
-nucleur
what are the units of energy
(J) joules
(kJ) kilojoules
what can not happen after non-renewable energy it’s are all used up
they can not be replaced
renewable energies
can not run out; can be replaced
positives and negatives of fossil fuels (coal, oil, gas)
(renewable or non-renewable)
+very reliable as we have good supplies at the moment
- when they are burned they produce carbon dioxide which contributes to global warming
non renewable
positives and negatives of nuclear resources
(renewable or non-renewable)
+ does not produce carbon dioxide or sulfur dioxide
- risk of radioactive material being released into the environment
non renewable
wind
(renewable or non-renewable)
+ no release of carbon dioxide or sulfur dioxide
- if there is no wind, there is no electricity
renewable
water (wave, tidal, or hydroelectric)
(renewable or non-renewable)
+ no release of carbon dioxide or sulfur dioxide
- difficult for wave machines to produce large amounts of electricity
- tidal barrages destroy habitats
- hydroelectric floods farmland and pushes people from their homes
renewable
geothermal
(renewable or non-renewable)
+ no release of carbon dioxide or sulfur dioxide
- most parts of the world do not have suitable areas for geothermal
renewable
solar
(renewable or non-renewable)
+ no release of carbon dioxide or sulfur dioxide
- if there is no sunlight, there is no electricity
renewable
what are the four pathways for energy transfer?
mechanical ; forcing an object to move
electrical ; changes move due to a potential difference
heating ; difference in temperature
radiation ; electromagnetic waves
what are the types of heat transfer?
conduction - heat transfers in a solid (through the solid vibrating onto another solid, making more energy)
convection - heat travels in fluids
radiation - heat travel via infrared (thermal) radiation
which type of heat transfer can travel through a vacuum
radiation
how do you calculate efficiency (%)
useful energy transferred (joules) / total energy supplied (joules)
x 100
how and in what metric are forces measured in
(N) newtons with a newton meter
name the 10 types of force
- friction
- lift
- magnetic force
- tension
-thrust
-upthrust - air resistance
- water resistance
- weight
- normal force
what is the equation for pressure ? and with what metric
p = force / area
metics
(pa or N/m^2). = (N) / (m^2)
what is pressure?
it is a measure on how spread out a force is
what is the equation for speed and what are the metrics?
speed (m/s) = distance (m) / time (s)
what is velocity?
it is the same as speed but also tells you which direction it is in (e.g forwards or backwards)
what is mass? what is the metric?
mass is a measure on how much matter an object is made up of, measured in kilograms
