Physics

• Described by magnitude only; e.g. distance, mass, volume, time, speed

  scalar quantities
• require both magnitude and direction; e.g. displacement, velocity, accelaratio

  Vector quantities
• acceleration is always due to gravity


  Free fall
• a combination of horizontal and vertical motions

  projectile motion
• UNIFORM CIRCULAR MOTION

  • velocity - straight out; tangent to the circle
  • accelaration - toward the center of the circle (centripetal)
• NEWTON'S THREE LAWS OF MOTION

  • First Law: Inertia - resistance to any change in motion
  • Second Law: Acceleration
  • Third law: Action and Reaction - for every action there is an equal but opposite reaction
• NEWTON LAW OF UNIVERSAL GRAVITATION - everything pulls on everything else with a force that depends on the masses of the objects and the distance between them
• • mass - amount of matter
  • weight - pull of gravity
  • volume - amount of space
  • density - how compact the particles are; amount of matter per unit volume
• • current - rate of flow of charges
  • resistance - opposition to the flow of charges
  • voltage - potential difference that causes charges to flow
• TYPES OF RADIATION

  • alpha radiation - fast‐moving helium; high energy, but due to their large mass, they are stopped by just few inches of air, or a piece of paper
  • beta radiation - fast‐ moving electeons able to penetrate farther, through several feet of air or several milliliters of plastic or very light metals
  • electromagnetic radation - a term used to describe all the different kinds of energies released into space by stars
• used in transmission of data via television, mobile phones, and radio

  radio waves
• the range in which the stars emit most of their radiation and the spectrum that thehuman eye is most sensitive to

  visible radiation
• very energetic, can break chemical bonds making molecules unusually reactive or ionizing them, changing their physical behavior; can damage DNA molecules

  ultraviolet radiation
• can pass through most substances, can bes used to "see through" objects

  x-rays
• photons, just like light, except of much higher energy

  gamma rays
• the highest point in a wave

  crest
• the lowest point in a wave

  trough
• the length of one complete wave (from one crest to the next)

  wavelength
• height of a wave

  amplitude
• time duration of a single wave

  period