P1 Flashcards
How to calculate Kinetic energy?
kinetic energy = 0.5 × mass × speed ^2
Ek = 0.5mv^2
How to calculate elastic energy?
elastic potential energy = 0.5 × spring constant × extension^2
Ee = 0.5ke^2
How to calculate gravitational potential energy?
g . p . e . = mass × gravitational field strength × height
gpe = mgh
What are the units for the spring constant?
N/m
What are the units for gfs?
N/kg
Power definition?
Power is defined as the rate at which energy is transferred or the
rate at which work is done.
What are the equations for Power?
Power = current x Voltage
Power= Current ^2 x Resistance
Efficiency equations?
Efficiency = useful output energy / total input energy x 100
Efficiency = useful power output / total power input x 100
Ways of reducing wasted energy transfers?
- Lubrication: prevents kinetic energy from being shifted into thermal energy due to the force of friction
- Insulation: prevents energy being lost as insulation has a low thermal conductivity, so, insulation transfers the thermal energy through the material slowly
Work done equation?
Work done = force x distance
Non-renewable sources definition?
Energy resources that will eventually run out
Renewable energy sources definitions?
Energy resources which can be replaced as they are used
Non - Renewable resources?
- Fossil Fuels: Coal, oil, gas
- Nuclear
Renewable Energy Sources?
- Wind
- Biofuel
- Hydroelectricity
- Geothermal
- Tidal
- Solar
- Wave
How does a fossil fuel/biofuel station generate electricity?
Fuel is burnt to heat water which turns to steam which powers the generator to generate electrcity
What are the energy stores?
- Magnetic & Electric: Electromagnetic field
- Elastic: Stretching
- Nuclear: Atoms
- Gravitational Potential: Height
- Thermal: Radiation
- Chemical: Food
- Kinetic: Moving
- Vibrational: sound
Energy Pathways?
- Light, sound, heating, electric current
- Carry energy from one store to another
Specific Heat Capacity explained…
- The larger the heat capacity, the more SHC
- If an object can store more heat, it will loose it slower
Hooks law?
- When mass is added to a spring, it applies a force which causes the spring to change shape and extend, now having energy in its elastic energy store
- Hooks law states that Force is directly proportional to the Extension
- And if shown as a graph, the gradient would be the spring constant
