PHYSICS

• Mass Density


  The mass of a substance divided by its volume
• Pressure


  The magnitude of the force acting perpendicular to a surface divided by the area over which the force acts
• SI Unit of Pressure: 1 N/m2 = 1 Pa (Pascal)
• Pressure is a scalar quantity (it has no direction)
• Atmospheric Pressure at Sea Level: 1.013 x 10^5 Pa = 1 atmosphere
• Pressure and Depth in a Static Fluid

  Pressure varies with depth h, in a fluid with uniform density
• Pressure does not depend on the size or shape of the container and the amount of fluid
• Pascal's Principle


  Any change in the pressure applied to a completely enclosed fluid is transmitted undiminished to all parts of the fluid and enclosing walls
• Archimedes' Principle


  Any fluid applies a buoyant force to an object that is partially or completely immersed in it; the magnitude of the buoyant force equals the weight of the fluid that the object displaces
• When an object is submerged (partially or completely), the volume submerged is equal to the volume of fluid displaced
• Archimedes' Principle

  1. If FB does not balance the weight: Case 1: FB > Wobj Object accelerates upward until it is partially submerged. The volume submerged will adjust (decrease) until such that the buoyant force balances the weight, then object will remain floating

  2. Case 2: FB < Wobj Object will accelerate downward since there is a net force downward. In other words, the object will sink with constant acceleration
• Steady Flow


  The velocity of the fluid particles at any point is constant as time passes
• Streamlines


  Used to represent the trajectories of the fluid particles in steady flow
• Unsteady Flow


  The velocity of the fluid particles at a point changes as time passes
• Turbulent Flow


  An extreme kind of unsteady flow in which the velocity of the fluid particles at a point change erratically in both magnitude and direction
• Fluid flow types

  • Compressible
  • Incompressible
  • Viscous
  • Nonviscous
• Equation of Continuity

  Volume flow rate Q = Av, where Q has the same value at every position along a tube that has a single entry and a single exit for fluid flow
• Bernoulli's Principle


  • The fluid accelerates toward the lower pressure regions
  • As the speed of a moving fluid increases, its pressure decreases
  • Flow speed and fluid pressure are inversely proportional
  • Elevation and fluid pressure are inversely proportional
• Applications of Bernoulli's Principle

  • Lift on wings
  • Curved trajectory of spinning balls
• Common Temperature Scales

  • Ice point - temperature at which ice melts
  • Steam point - temperature at which water boils (at 1 atm pressure)
  • Temperatures reported in degrees Celsius (°C) or degrees Fahrenheit (°F)
  • Temperature change (or difference) reported in Celsius degrees (°C) or Fahrenheit degrees (°F)
• Reasoning Strategy for Temperature Conversion

  1. Determine the magnitude of the difference between the stated temperature and the ice point on the initial scale

  2. Convert this from one scale to the other using the appropriate conversion factor

  3. Add or subtract the number of degrees on the new scale to or from the ice point on the new scale
• Kelvin Temperature Scale

  • TK = TC + 273.15
  • Ice point is 273.15 K
  • Defines the lowest possible temperature, absolute zero, 0 K
• Linear Thermal Expansion


  The length of an object changes when its temperature changes
• Volume Thermal Expansion


  The volume of an object changes when its temperature changes
• Heat


  Energy that flows from a higher-temperature object to a lower-temperature object because of a difference in temperatures
• Internal Energy


  The heat that flows from hot to cold originates in the internal energy of the hot substance
• It is not correct to say that a substance contains heat
• Heat supplied or removed in changing the temperature of a substance

  • Solids and Liquids
  • Gases
• Calorimetry


  If there is no heat loss to the surroundings, the heat lost by the hotter object equals the heat gained by the cooler ones
• Heat and Phase Change: Latent Heat

  • Latent heat of Fusion (solid to liquid and vice versa)
  • Latent heat of Vaporization (liquid to gas and vice versa)
  • Latent heat of Sublimation (solid to gas and vice versa)
• Convection


  The process in which heat is carried from one place to another by the bulk movement of a fluid
• Conduction


  The process whereby heat is transferred directly through a material
• The amount of heat Q that is conducted through a bar depends on the time, temperature difference, cross-sectional area, and length of the bar
• Radiation


  The process in which energy is transferred by means of electromagnetic waves
• A material that is a good absorber is also a good emitter, and a material that absorbs completely is called a perfect blackbody
• Atomic Mass Unit (u)


  The unit used to facilitate comparison of the mass of one atom with another, with the reference element being the most abundant type or isotope of carbon, called carbon-12
• Mole


  One mole of a substance contains as many particles as there are atoms in 12 grams of the isotope carbon-12
• Avogadro's Number


  The number of atoms per mole
• The mass per mole (in g/mol) of a substance has the same numerical value as the atomic or molecular mass of the substance (in atomic mass units)
• Ideal Gas


  An idealized model for real gases that have sufficiently low densities, where the molecules are so far apart that they do not interact except during (elastic) collisions