physics- energy

Cards (108)

  • Energy can be transferred between objects by doing work on them or heating them up, but cannot be created or destroyed.
  • change in gravitational potential energy = weight * change in height
  • the unit of gpe is J or Kj
  • to measure the thickness of a piece of aluminum foil, use a micrometer screw gauge
  • wind energy, wave energy, tidal energy, biofuels, solar cells, biofuel all depend on the sun
  • energy from nuclear fusion occurs when two nuclei are fused together to form one heavier nucleus
  • nuclear fusion releases more energy than nuclear fission because it produces less mass
  • in nuclear fusion, the mass lost is converted into energy according to E=mc^2
  • geothermal and nucler dont derive energy from the sun
  • tides are renewable because they are always there and they are continuous
  • the equation of kinetic energy is E = 1/2 x m x v^2
  • The gas molecules have mass and great speed, especially if the temperature is increased. They move in directions, exerting force on the walls of a container, and move continuously and frequently. Force is exerted by particles due to the rate of change of momentum. momentum changes when particles hit walls. Pressure is a force of molecules per unit area
  • when pressure increases, volume decreases
  • when temperature increases within a constant volume, there is a greater change of momentum, the particles collide with the walls of the container with greater force, so they move faster with more kinetic energy
  • Pv= constant 
    p1v1= p2v2
    p1v1/p2= v2
  • specific heat capacity = energy required / mass * temperature increase
  • specific heat capacity= energy required per unit mass per unit temperature increase
  • energy can be divided into energy stores and energy transfers. Transfers; electrical, thermal, radiation,mechanical. BUT STORES; kinetic, gpe, chemical, elastic strain energy, nuclear energy, internal energy, electrostatic energy
  • A SOLID HAS FIXED shape and volume, liquid has fixed volume but will take shape of container, gas expands to fill container no fixed shape or volume
  • the first law of thermodynamics states that energy cannot be created nor destroyed only transferred from one form to another.
  • Thermal conductivity is how well an object conducts heat through it. The higher the value, the better the conductor of heat.
  • Thermal conductivity - how well something conducts heat
  • muscles store chemical energy
  • if you lift an object upwards you give it gravitational potential energy
  • kinetic energy is the energy store of a moving object
  • gpe is the energy store of an object raised up against the force of gravity
  • energy= quantity that must be changed or transferred to make smth happen
  • the higher an object above the ground the higher its gpe. when u let the object fall you get energy back
  • uranium is a nuclear fuel
  • a fuel is a store of chemical energy because when the fuel is burned the stored energy is released
  • all radioactive materials are stores of nuclear energy
  • in radioactive materials, energy is stored in the nucleus of the atom.
  • nuclear power stations are designed to release nuclear energy stored in uranium
  • when you stretch a rubber band, it becomes a store of strain energy
  • when you heat an object so it gets hotter you are giving energy to its atons
  • the energy stored in a hot object is internal energy. Internal energy ; the energy of an object. The total kinetic and potential energies of its particles
  • thermal energy; energy transferred from a hotter place to a colder place because of the temperature differnce between them
  • solids cant flow and theyre not compressible
  • centre of gravity is the point in an object where distribution of weight is equal in all directions
  • the internal energy of an object will be higher if;
    • particles are moving faster ((higher kinetic energy)
    • or if the particles are further apart (( bigger potential energy))