Physics 2

• Frequency


  Number of waves per unit time
• Frequency


  Number of waves/cycles per second
• Amplitude


  Maximum displacement from the rest position
• Wavelength


  Distance between 2 consecutive crests or troughs
• Resultant force


  The single force that could represent all the forces acting on an object
• No resultant force: objects stays at rest or travels at a constant speed
• Has resultant force: Changes speed
• Force Spring

  Force = Spring constant x Extension
• Density


  Mass per unit volume of a substance
• Moment


  Force x perpendicular distance from pivot
• Convection


  When water or gases are heated, they become less dense, rise and cooler water/gas replaces it
• Infrared radiation


  Heat emitted from warm objects, which can travel through a vacuum
• Dark objects


  Good absorbers and emitters of heat
• Light objects


  Good reflectors of heat
• Heat


  A form of energy measured in Joules
• Temperature


  Measure of how hot or cold an object is
• Conductors


  Materials that allow heat energy to flow through them easily
• Insulators


  Materials that don't allow heat energy to flow through them easily
• Transverse waves


  Particles in the medium vibrate perpendicular to the direction of the wave
• Longitudinal waves


  Particles in the medium vibrate parallel to the direction of the wave
• Waves


  Method of transferring energy from one place to another through vibrations
• Electromagnetic Spectrum


  • Radio
  • Micro
  • Infrared
  • Visible
  • Ultraviolet
  • X-ray
  • Gamma
• Directly proportional


  Quantities that have a straight line relationship through the origin
• Hooke's Law


  Extension of a spring is directly proportional to the load applied, provided the limit of proportionality is not exceeded
• Pressure


  Force per unit area
• Principle of moments


  When an object is in equilibrium, the sum of the clockwise moments about a point equals the sum of the anticlockwise moments about the same point
• Centre of gravity


  The point on an object where all the object's weight appears to act
• Types of forces


  • Gravity
  • Magnetic
  • Weight
  • Friction
  • Electrostatic
  • Air resistance
  • Tension
• Electromagnetic waves


  Can travel through a vacuum at 3x10^8 m/s, all are transverse waves
• Gamma rays


  Have higher frequency, more waves per second, more energy, more dangerous to humans
• Insulators


  Have gaps that trap air particles, reducing heat loss
• Upthrust


  Upwards force acting on an object immersed in a fluid
• Normal reaction


  Upwards force on an object due to the surface it sits on
• Mechanical advantage


  When a force is applied at a distance from the pivot, reducing the effort required
• Mass


  The quantity of matter within an object
• Normal reaction 


  Upwards force on an object due to the surface it sits on
• Drag


  Friction force of an object in water
• Air resistance 


  Friction force of an object in air
• Electrosratic 


  Attractive or repulsive force by charged objects
• Magnetic 


  Attractive or repulsive force caused by a magnet