Key terms

• Precision


  An indication of the agreement among a number of measurements made in the same way (a measure of exactness)
• Systematic Error


  An error associated with a particular instrument or experimental technique that causes the measured value to be off by the same amount each time, affects the accuracy of results, can be eliminated by fixing the source of error
• Law of Conservation of Linear Momentum - The total momentum of an isolated system remains constant
• Derived Units

  • Combinations of fundamental units, may or may not have a separate name
• Scalar


  A quantity with magnitude only
• Kinetic Energy

  Product of ½ times the mass of an object times the square of an object’s speed
• Linear Momentum


  Product of mass and velocity
• Efficiency


  The ratio of the useful energy output to the total energy input
• Inelastic Collision - a collision in which kinetic energy is not conserved
• Principle of Conservation of Energy - The total energy of an isolated system remains constant
• Vector


  A quantity with both magnitude and direction
• Random Uncertainty


  An uncertainty produced by unknown and unpredictable variations in the experimental situation, affects the precision of results, can be reduced by taking repeated trials but not eliminated
• Accuracy


  An indication of how close a measurement is to the accepted value (a measure of correctness)
• Impulse


  Change in momentum
• Work


  The product of a force on an object and the displacement of the object in the direction of the force
• Mechanics

  1. Displacement - distance traveled in a particular direction (change in position)

  2. Velocity - rate of change of displacement

  3. Speed - rate of change of distance

  4. Acceleration - rate of change of velocity
• Elastic Collision - a collision in which kinetic energy is conserved
• Power


  The rate at which work is done or the rate at which energy is transferred
• Translational Equilibrium - net force acting on a body is zero
• Change in Gravitational Potential Energy

  Product of an object’s mass times the gravitational field strength times the change in height
• Fundamental Units of the SI measurement system

  • kilogram
  • second
  • mole
  • meter
  • ampere
  • Kelvin
  • candela
• Escape Speed


  Minimum speed of a rocket needed to escape the gravitational attraction of a planet
• Gravitational Potential Energy (EP)


  The work done in moving a mass from infinity to a point in space (the work done is path independent)
• Newton’s Universal Law of Gravitation

  The force of gravity between two objects is directly proportional to the product of the two masses and inversely proportional to the square of the distance between them and acts along a line joining their centers
• Thermal Capacity (C)


  Energy required to raise the temperature of a substance by 1K
• Thermal Energy (Heat) (Q)

  Energy transferred between two substances in thermal contact due to a temperature difference
• Molar Mass


  The mass of one mole of a substance
• Absolute Zero of Temperature


  Temperature at which a gas would exert no pressure
• Specific Latent Heat (L)

  Energy per unit mass absorbed or released during a phase change
• Ideal Gas


  A gas that follows the ideal gas equation of state (PV = nRT) for all values of P, V, and T (an ideal gas cannot be liquefied)
• Gravitational Field Strength (g)


  Gravitational force per unit mass on a point mass
• Kepler’s Third Law

  The ratio of the orbital period squared to the average orbital radius cubed is constant for all planets
• Gravitational Potential (V)


  The work done per unit mass in moving a mass from infinity to a point in space
• Avogadro constant (NA)


  The number of atoms in 0.012 kg of 12C ( = 6.02 x 10^23)
• Mole


  An amount of a substance that contains the same number of atoms as 0.012 kg of 12C
• Internal Energy of a substance (U)

  The total potential energy and random kinetic energy of the molecules of the substance
• Specific Heat Capacity (c)


  Energy required per unit mass to raise the temperature of a substance by 1K
• Temperature (T)

  a. The property that determines the direction of thermal energy transfer between two objects. b. A measure of the average random kinetic energy of the particles of a substance
• Pressure (P)


  Force per unit area acting on a surface
• Real Gas


  A gas that does not follow the ideal gas equation of state for all values of P, V, and T (a real gas can approximate an ideal gas in some circumstances)