Card Set Information

2011-04-19 08:35:20

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  1. translational motion:
    distance, velocity, acceleration. time
    x = x0 + v0t + (1/2)at2
  2. translational motion:
    velocity, acceleration and distance
    v2 = v02 + 2ax
  3. translational motion:
    velocity, acceleration and time
    v = v0 + at
  4. how does a projectile stay in motion? what keeps it in motion?
  5. peak height of a projectile
    v0 = sin(0) - sq.rt.(2gh)
  6. horizontal distance traveled of a projectile
    x = vt . cos(0)
  7. peak velocity
    no velocity, but acceleration = 10
  8. PE and KE of projectile object at its peak
    • PE is maximized
    • KE is minimized

    (energy must be conserved)
  9. projectile path is independent of....
  10. two objects launched with the same velocity will...
    hit the ground at the same moment
  11. what determines the time of flight?
    vertical velocity
  12. range of projectile is maximized at what angle from the horizontal?
  13. symmetry of projectile says what? (speed wise)
    upward mirrors downward -

    initial speed = final speed
  14. air resistance is greater on (surface area, shape, and speed)
    • larger surface area
    • irregularly shaped
    • greater speed
  15. does mass affect force or path of air resistance
    force = no

    path = yes
  16. how does greater mass affect air resistance
    force is the same, so it decreases acceleration

  17. centripetal force (equation)
    F = m . v2/r
  18. inertia
    tendency of an object to stay in present state of motion

    (keeps projectile in motion)
  19. law of universal gravitation
    F = G(m1m2)/r2
  20. friction points in what direction?
    always parallel to surface
  21. equation for torque
    t = F r sin0
  22. if the board has mass, what do you do with torque?
    F=mg at center of board
  23. equation for work (not for gases)
    W = Fd cos0
  24. what direction is friction (relative to work)?
    friction does negative work!
  25. work done lifting an object
    W = Fd = mg x h
  26. what is gravitational potential energy?
    work done by gravity:

    change PE = -W
  27. energy and power
    energy = work + heat

    so, P = (w + q)/s
  28. 1 revolution is equal to
    2 pi r
  29. equation for angular momentum
    L = l x m x v

    l = lever arm, mv = linear momentum
  30. elastic collision
    mechanical energy is conserved
  31. inelastic collision
    mechanical energy is lost to internal energy (heat)
  32. perfect inelastic collision
    2 objects stick together
  33. reverse inelasitc collisions (object dissipates into 2 sep. objects). In what direction do they travel
    opposite to each other
  34. ex: man standing on a board and jumps off

    what do you need to consider when determining their final positions?
    move in opposite directions

    consider their centers of gravity
  35. what is impulse?
    change in momentum
  36. Machine: inclined plane (how is work minimized?)
    straight up: W = ugh

    ramp: W = mg x sin x h
  37. What is theta equal to in the ramp
    height of ramp / distance of the ramp

    the greater the distance (d) the smaller the angle, the less work needed
  38. Machine: lever (torque)

    what does F need to equal to lift mass?
    F = mg in opposite direction
  39. How do you decrease the force required to life the object?
    increasing the lever arm

    (doubling lever arm, reduces force by a factor of 2)
  40. In a pulley, what is the tension in the rope?

    Tension = Force
  41. In a double pulley system, what is the force required to lift mass m?
    F = T

    T = 2mg

    F = (mg)/2
  42. alpha decay
    2 protons, 2 neutrons
  43. traveling of alpha particle
    not far

    stopped by skin, paper
  44. beta decay
    expulsion of an e-
  45. positron
    B+ is emitted (-1 atomic #)
  46. electron capture
    gain e- (-1 atomic number
  47. frequency of a gamma particle
    high frequency particle
  48. rest mass energy
    E = mc2
  49. fussion combining 2 (?) from (?)
    combining 2 nuclei

    from a heavier nucleus
  50. fission
    splitting a single nucleus into 2 lighter nuclei
  51. where does energy for fusion and fission come from?
    mass defect
  52. density formula
    density = m/v
  53. density constant for gases and liquids?
    constant for liquids and solids

    change for gases, because they are compressible
  54. What is specific gravity?
    density of a substance compared to density of water
  55. so specific gravity of water is
  56. formula for fluid pressure
    P = F/A
  57. Do fluids at rest have uniform density in a sealed container?
  58. What is the pressure experience by fluids at rest with uniform density?
    P = density x g x y

    y = depth of fluid
  59. Where is pressure greatest for a fluid at rest?
    greatest depth (P=pgy)
  60. What if you have many fluids layered in a sealed container?
    P = (pgy)1 + (pgy)2 + (pgy)3...........
  61. What is the pressure of a fluid at rest with uniform density in an open container
    add atmospheric pressure to density x g x y
  62. hydraulic lift (equation)
    pressure is transferred completely:

    F1/A1 = F2/A2
  63. What is the velocity of a fluid flowing (if you don't know rate or area)?
    v = sq.rt (2gh)
  64. buoyant force
    upward force acting on a submerged object
  65. what is buoyant force equal to? (not equation)
    weight of fluid displaced by submerged object
  66. equation for buoyant force
    FB = (density of fluid) x (volume) x (g)
  67. floating object -
    submerged portion of object =

    density of object/density of fluid
  68. How much of an object will float in water if its specific gravity is 0.4?
  69. does buoyant force change with depth?
  70. What is the apparent mass on an object (when it is submerged)?
    mass of the fluid displaced

    thats why we weigh so little in water
  71. equation for fluid flow
    Q = (area)(volume)
  72. does fluid flow faster in a wider pipe, or a more narrow pipe?
  73. ideal fluid flows at a constant rate
    K = Pressure + (density)(g)(h) + (1.2)(p)(v2)

    K is constant, specific to fluid in a flow
  74. surface tension and temperature
    increase temperature = weaker surface tension
  75. formula for stress
  76. formula for strain
    change in dimension/original dimension
  77. what are stress and strain
    stress is done on an object

    strain is how the object responds
  78. modulus of elasticity
  79. What is Coloumb's law? (equation) What does it mean?
    describes force between two charges

    F = k (q1q2) / r

    k = 9 x 109
  80. Coloumb's law resembles what? But?
    gravitational force (G)(m1m2)/(r2)

    • but, gravitational force is attractive
    • electrical force is repulsive
  81. electric field - in what way are the lines drawn? What does the length of the line indicate?
    (+) ----------------> (-)

    length = strength

    (smaller is stronger)
  82. What is the electric field created by charge Q?
    E = k x (Q)/(r2)
  83. What is the force felt by charge q in the electric field E?
    F = E x q
  84. What makes and feels the field?
    Q makes the field

    q feels the field

    [F = k x (Qq)/(r2)
  85. What is the potential energy of of the charge in electric field?
    Potential energy (U) = force x displacement (like ugh)

    U = Eq x h
  86. How does potential energy change when moving perpendicular to electric field?
    doesn't change

    same way that moving parallel to surface of the earth doesn't change gravitational potential energy
  87. What is an electric dipole?
    created by 2 opposite charges with equal magnitude
  88. (+) and (-) fall/rise to lower/higher potential?
    + charge falls to a lower potential

    - charge rises to a higher potential
  89. high/low potential and +/- potenital
    • high potential = + potential
    • low potential = - potential
  90. How do we measure movement of a charge?
    current (A)
  91. So, what is current? (How is it measured)
  92. Current flows in what direction (relative to potential energy)
    current flows from high potential to low potential
  93. In what direction does current flow (relative to electron flow or electron velocity)?
    current moves in opposite direction of e- flow
  94. conducting electricity: what are good conductors and poor conductors?
    • good = allow e- to flow freely [metals]
    • poor = hold e- tightly in place [resistors]
  95. What is induction?
    charging a conductor
  96. circuit equations: current, voltage, resistance, capacitance
    V = IR

    I = Q/t

    C = Q/V
  97. what is capacitance?
    ability to store charge per unit voltage [Q/V]
  98. voltage is the same thing as...... and it depends on
    potential energy

    depends on distance
  99. plates that are further apart will have greater/less voltage and capacitance?
    greater voltage

    less capacitance
  100. What is a capacitor?
    temporarily stores energy in a circuit
  101. What is the separation of charges in a capacitor?
    emf between the plates
  102. what is resistance?
    resistance to flow of charge
  103. resistance is directly proportionate to what?
    length of wire

    [R = density x (length/area)]
  104. resistance and temperature
    resistance increases with temperature

    [thermal oscillations impede with flow]
  105. Kirchoff's Rules:
    - amount of current flowing in and out
    - voltage around the circuit
    - amount of flow in = amount of flow out

    - votalge around any path in circuit must sum = 0

    - battery adds energy to circuit
  106. How does battery add energy to the circuit?
    increases voltage from one point to another

    (emf = voltage added)
  107. Diaelectric constant (K)
    substance between plates of a capacitor

    • -must be insulator to separate charge
    • -resists creating EF, in order to store energy
  108. Resistors in series/parallel

    what is constant?
    series = add [current is constant]

    parallel = 1/R [voltage is constant]
  109. what is the terminal voltage? (equation)
    V = emf - IR
  110. AC Current - what's going on?
    e- don't move in one direction,

    they oscillate back and forth
  111. maximum current and maximum velocity in an AC Current
    Vmax = sqrt.(2) x Vmax

    Imax = sqrt.(2) x Imax
  112. What creates a magnetic field?
    charging electric field

    currents (moving charges) creates the magnetic field
  113. + and - of electric field corresponds to what in magnetic field?
    north and south

    north = + and south = -
  114. In what direction do magnetic lines point?
    north -------> south
  115. Doess a stronger magnetic field have closer lines, or further apart?
    closer lines = stronger fied
  116. How does the KE of a particle moving through the magnetic field change?
    no work done by the magnetic field, means no change in KE due to the magnetic field
  117. What is magnetic force?
    F = q x V x B x sin(0)
  118. force is applied in what direction relative to both velocity and magnetic field
    force is perpendicular to both velocity and magnetic field
  119. What is the work done by magnetic force?
    no work:

    because it's perpendicular to velocity
  120. What way does magnetic field act?
    like centripetal force (mv2/r)

    because charged particle moves in a circle
  121. What will move through a magnetic field with a smaller radius: a proton or an electron

    because it has smaller mass [F = mv2/r]
  122. Right Hand Rule
    thumb = direction of current

    fingers = direction of magnetic field

    palm = direction of force
  123. What results from a change in magnetic field?
    an electrical field
  124. What happens to the mechanical energy in a magnetic field when it is changed and creates an electric field?
    mechanical energy to create the field is dissipated as heat
  125. What is the magnetic flux?
    number of magnetic fields running through the loop
  126. what does change in magnetic flux do?
    induces an emf
  127. What is a magnetic field generated by?
    a moving charge
  128. moving charge experiences what when moving through a magnetic field?
    force = qvBsin0
  129. In what direction is this force?
    perpendicular to velocity and magnetic field (B)
  130. At equilibrium, in an electric and magnetic field, what is the net force acting on a particle?

    force from electric field = force from magnetic field

    Eq = qvBsin(0)
  131. How can we find the acceleration or distance of a particle traveling through an electric or magnetic field
    F = ma

    set force (Eq) or (qvbsin) = mass x acceleration

    distance = (1/2)at2