Physics energy and waves

• Kinetic energy is the energy an object has because it is moving.
• The equation for Kinetic Energy is 0.5xmxv^2
• Gravitational potential energy is when objects are lifted up, they gain gravitational potential energy.
• The equation for GPE = mxgxh
• the wave equation = velocity = frequency x wavelength
• Waves can be transverse or longitudinal
• Work done = the energy transferred
• power = the rate of the energy transfer
• The stores of energy are: Kinetic, GPE, Elastic, Magnetic, Electrostatic, Thermal, Nucleur, Chemical.
• The transfers of energy are: Mechcanically, Electrically, By radiation and by heating.
• The equation for efficency = useful/total x 100
• Renewable energy can
• Renewable energy will not run out, Non-Renewable will run out
• Fossil fuels are non renewable
• Waves transfer energy from one

  place to another.
• In longitudinal waves,

  the vibrations are parallel

  to the direction of wave

  travel.

  In transverse waves, the

  vibrations are at right

  angles to the direction of

  wave travel.
• The speed of light is

  always constant at

  300,000,000 m/s
• All electro-magnetic waves

  travel at the speed of light.
• All EM waves reflect if they

  hit a reflective surface.
• angle of incidence (°) = angle of reflection (°)
• The electro-magnetic (EM)

  spectrum is a family of 7 waves.

  They are all transverse and travel

  at the speed of light
• The three EM waves with

  the most energy are

  ionising:

  UV

  X-rays

  Gamma rays
• Gamma

  Sterilise food/medical

  equipment

  Kill cancer cells (radiotherapy)

  Ionising. Can

  damage/mutate cells &

  cause cancer.
• X-rays

  Imaging luggage.

  X-raying bones.

  Ionising. Can

  damage/mutate cells &

  cause cancer.
• Light

  Seeing

  Endoscopes

  Fibre-optic

  communication

  Blindness
• Ultraviolet

  Sun beds

  Security marking.

  Sun Burn

  Ionising. Can damage/mutate

  cells & cause cancer.
• Infrared

  Remote controls

  Heating

  Night vision

  Skin burns
• Microwaves

  Satellite communication

  mobile phones

  Cooking

  Internal tissue heating.
• Radio waves

  Radio

  TV