stored energies - Sp3 Flashcards
what is the equation for gravitational potential ?
mass x gravitational field strength x change in vertical height
what factors affect kinetic energy stored in an object?
mass and speed
what is the equation for kinetic energy?
1/2 x mass x speed
Explain with examples, how energy is conserved
the law of conservation of energy sates that energy cannot be created nor destroyed but can change form into other stores. for instance, energy in a motor is transferred from chemical energy into kinetic energy and thermal energy
what are the different types of energy stores?
kinetic, thermal, chemical, nuclear, gravitational potential, elastic potential, electrostatic, magnetic
give 2 examples of energy being moved through stores
spring: elastic potential -> kinetic
object at high height: gravitational potential -> kinetic (falling)
what are energy efficiency diagrams called?
Sankey diagrams
how to calculate the percentage of efficient outcome energy?
efficient outcome/total outcome x 100
what happens to wasted energy in energy transfers?
the energy turns into different stores (such as heat or sound)
explain one way energy is transferred wastefully by a mechanical process
the thermal energy produces from a running engine (any other example is fine! I believe ur right (::)
How can we reduce unwanted energy transfers
lubrication to prevent friction, thermal insulation to prevent thermal loss, streamlining for flying objects
what is the definition of efficiency?
how good an object is at at transferring energy input into useful energy output
how can efficiency be increased?
by reducing unwanted energy transfers
Describe the ways in which energy can be transferred by heating
conduction, convection or radiation
how to reduce unwanted energy through thermal insulation
double glazing, cavity walls, loft insulation etc
what is the definition of thermal conductivity?
the measure of how well a material conducts thermal energy when it’s heated
Describe the effects of the thickness and thermal conductivity of the walls of a building on its rate of cooling
the thicker and the lower the thermal conductivity, the slower the rate of cooling and vies vera
how do different factors affect the gravitational potential energy stored in an object
the mass of the object, the distance between ground and object - the heavier and the higher, the greater the gravitational potential energy stored
describe how different factors affect the kinetic energy stored in an object
mass + speed - the bigger the object and the faster it travels, the more kinetic energy stored
list 3 non-renewable energy sources
fossil fuels, nuclear fuel, coal, oil, gas
list 2 advantages and disadvantages of non-renewable fuel
advantages: cheap and reliable for current demand
disadvantages: environmental impact and will not last for long future (not sustainable)
list 3 renewable energy sources
bio-fuels, wind, sun, hydro-electricity and tides
list 2 advantages and disadvantages of renewable fuel
advantages: last a very very long time and do less damage to the environment
disadvantages: expensive and don’t provide much energy so wont always be able to keep up with demand
explain how the use of non-renewable energy sources is changing
coal and gas power stations can now re-use wasted heat - making the most of fossil fuels makes them more sustainable and boosts efficiency of resources
list 3 renewable energy sources used today
wind mills, solar panels, tidal barrages
describe the sources of energy for different renewable resources
plant, wind, solar, tidal
describe different ways in which the sources of energies are used
plant matter = bio fuel, wind = wind mills, solar = solar panels, tidal = tidal barrages
explain why we cant ONLY use renewable sources
because on cloudy days when the sun isn’t out, solar panels are ineffective, when there is little wind, wind mills are ineffective and so on. there are many natural variables we must depend upon for these energies to provide us. so when these sources do not work to their full amount, we must use fossil fuels etc to keep up with demand
how is the use of renewable energy changing?
prices for renewable energy technologies are dropping to make using renewable energy an affordable solution
