physics topic one Flashcards
describe mechanical force pathways
Mechanically – when a force acts and an object moves
describe electrical force pathways
Electrically – when an electric current flows
describe heating force pathways
Heating – a temperature difference between objects
describe radiation force pathways
Radiation – electromagnetic waves or sound
what happens to all wasted energy
dissipates to the surroundings
what is work done
work done is the amount of energy transferred by a force
what is the formula for work done
Work (J) = Force (N) x Distance (m)
what is electrical work
Electrical work is work
done when charge flows in a circuit is the amount of energy
transferred.
what is the formula for energy transferred / electrical work
Energy transferred (Work) (J) = Charge flow (Q) x Potential difference (V)
what do energy do stretched or bent objects have
Stretched or bent objects have elastic energy (Ee) if they have the ability to recover to their original shape and dimensions.
what is spring constant measured in
N/m
what energy does an object gain when it raises above ground
When an object is raised above ground level it gains
gravitational potential energy
what is gravitational field strength measured in
N/kg
what is specific heat capacity
the amount of energy required to raise the temperature of 1 kg of a substance by one degree Celsius.
what is the specific heat capacity required practical
1) Measure energy (transferred) using joulemeter or ammeter, voltmeter and stopclock
2) Measure mass of metal block using electric balance
3) Measure temperature change using thermometer
4) Use E = mcθ to calculate specific heat capacity
Valid results:
* Repeat practical and calculate a mean
* Plot a graph of temperature against time and use linear section of graph for temperature
change
what is the thermal insulators required practical
1) Use a measuring cylinder to measure volume of water
2) Put hot water in the metal can
3) Measure initial and final temperature with a thermometer
4) Use a stopwatch to measure 5 minutes
5) Calculate temperature decrease
6) Repeat with different number of layers of newspaper
7) Repeat with no layers of newspaper - as a control
what is power
the rate at which energy is transferred which is the rate work is done
what is power measured in
watts
what is thermal insulation used for
Thermal insulation is often used to reduce unwanted energy transfers.
what is thermal conductivity
how quick heat is transferred though a material so The higher the thermal conductivity, the quicker heat is transferred through the material.
what are non-renewable energy sources
energy sources will eventually run out
what are renewable energy sources
Renewable energy sources are those which can replenish
themselves in the short term, and so will never run out.
how does a coal fired power station work
coal has chemical energy
when burnt, heat energy
used to boil water/make steam
used to turn turbine(s)
which now have kinetic energy
turbines turn generators
where kinetic energy is transferred to electrical energy
advantages of renewable energy
Can be used over again
Doesn’t release Carbon
Dioxide
disadvantages of renewable energy
Unreliable – not always
sunny or windy
Usually expensive to build
advantages of non renewable energy
Reliable
disadvantages of non renewable energy
Releases Carbon Dioxide –
greenhouse gas leading to global warming
Can only be used once
