Topic 1- Motion, Forces And Conservation Of Energy Flashcards
(49 cards)
8 Energy stores
Kinetic, Thermal, Chemical, Nuclear, Magnetic, Electrostatic, Elastic Potential, GPE
Kinetic energy depends on…
Mass and speed
Greater the mass and the faster it’s going, the more kinetic energy
If you double the mass, the energy in the kinetic energy store…
Doubles
If you double the speed, the energy in the kinetic energy store…
Quadruples
Energy can be … , … between stores and …
But can never be … or …
The total energy of a closed system has…
Stored, transferred and dissipated
Can never be created or destroyed
No net charge
Energy can be transferred between stores in four main ways…
Mechanically
Electrically
By heating
By radiation
A ball rolling up a slope
The ball does work against the gravitational force
So energy is transferred mechanically from the mentor energy store of the ball to its gravitational potential energy store
A bat hitting a ball
Bat has energy in its kinetic energy store
Some out this is transferred mechanically to the balls kinetic energy store
Some is also transferred mechanically to the thermal energy stores of the bat, ball and surroundings
The rest is carried away by sound
Energy is only useful when…
It is transferred from one store to a useful store
Input energy is always … and … to the surroundings
Dissipated or wasted
Often to thermal energy stores
When work is done mechanically … have to be overcome eg.
Therefore…
Frictional forces eg. Things rubbing together and air resistance
Therefore energy needed to overcome this is transferred to thermal energy stores (not useful energy)
What reduces unwanted energy transfers
Lubricants- reduce friction between objects when they move usually liquids like oil, can flow easily between objects and coat them
Insulation- between walls of houses, lowest conductivity means slowest rate of energy transferred through them (thick walls and a air gap between the two walls)
Non renewable advantages
Reliable- can meet the current demand, use more fuel to release more energy
Cheap to build and run fossil fuel power plants
Low cost of extracting fossil fuels
Disadvantages of non renewable
Nuclear power plants cost a lot to build and cause safety issues
Slowly running out
Environmental problems, contribute to global warming
Cause acid rain
Oil spillages
Nuclear waste is dangerous
Renewable advantages
Never run out
Not as much impact on environment
Disadvantages of renewable
Don’t provide much energy
Not efficient
Weather dependant
Biofuels
Made from plants and waste
Can not respond to immediate energy demands
Cost lots
Increases methane and carbon dioxide emissions
Reliable because crops grow quickly
Wind power
Initial costs are high but minimal to run
No pollution
Lots of them are needed to produce lots of power
Spoil the view
Noisy
Only work when wind so can’t always supply to high demand
Solar cells
No pollution
Initial costs are high but minimal to run
Generate small scale electricity
Most suitable for sunny countries
No power made at night
Can’t increase production when there is extra demand
Hydro-electricity
No pollution
Big impact on environment due to flooding possible loss of housings or habitats
Immediately respond to increased electricity demand
Initial costs are high but minimal running cost
Generally reliable
Tidal barrages
No pollution Effect boat access Can spoil view Alter wildlife Reliable Don’t work when water levels are equal both sides Initial costs are high but minimal running costs No fuel costs
Vectors…
Have a magnitude (size) and direction
Vector quantities
Force Velocity Displacement Weight Acceleration Momentum
Scalar
Only have a magnitude and no direction
