Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

Uslides2

690 views

Published on

Class presentation slides for Physical Science 50 (second quarter) Spring Semester 2009

Published in: Education, Technology, Business
  • Be the first to comment

  • Be the first to like this

Uslides2

  1. 1. Aristotle Natural Motion
  2. 2. Galileo Experimentation 
  3. 3. Newton Newton’s Laws of Motion, Gravity 
  4. 4. Linear Motion distance SPEED = time 
  5. 5. Linear Motion displacement VELOCITY = time 
  6. 6. Earth -> Sun 1.497 x 1011m distance velocity = 3 x 108m/s  Time = = 498.9 seconds = 8.3 minutes
  7. 7. Sun -> Mars 2.28 x 1011m d 3 x 108m/s t = v= = 760.3 seconds = 12.67 minutes
  8. 8. Acceleration change in velocity  Acceleration = time
  9. 9. Deceleration = Negative Acceleration 
  10. 10. Saleen S7 Turbo vf– vi 60 mph – 0 mph mph a= t = 3.3 s = 18.2 s = 0.005 mi/s2
  11. 11. Gravitational Acceleration
  12. 12. Free Fall Acceleration due to GRAVITY  Mass doesn’t matter 
  13. 13. Gravitational Acceleration  Velocity increases at a constant rate vf - vi a= t 20m/s - 10 m/s = 1 second = 9.8 m/s2 = 32 ft/s2
  14. 14. Distance Fallen Distance = Velocityaverage x time  v i + vf = 2 x t 0 + gt = 2 x t = 1/2 gt2
  15. 15. Transamerica Building 46 g golf ball dropped  from top of Transamerica building  7.35 seconds to hit ground d = ???? 
  16. 16. Transamerica Building 46 g golf ball dropped  from top of Transamerica building  7.35 seconds to hit ground  d = 1/2gt2 = (0.5)(9.8 m/s2)(7.35s)2 = 265 m = 853 ft
  17. 17. g and elevation  ATT vs. Coors Field sea level 5280 ft 9.8185 m/s2 9.8136 m/s2
  18. 18. G force Extreme Acceleration  > 1g Breathing difficulties  blackout
  19. 19. Gravity
  20. 20. Newton’s Laws of Motion Every body continues in a state of rest 1) or in uniform motion in a straight line unless compelled to change that state by forces impressed upon it. INERTIA
  21. 21. Inertia
  22. 22. Newton’s Laws of Motion 2) The acceleration produced by a Force acting upon on body is directly proportional to the mass of the body. F=mxa
  23. 23. Force Units F =m x a  = 2000 kg x 0.05 m/s2 = 100 kg m/s2 = 100 Newtons
  24. 24. Force of Gravity F=mxa  Fg = m x g  Fg = WEIGHT 
  25. 25. Mass vs. Weight  60 kg person Weight = m x g Earth Moon Jupiter (60 kg)(9.8m/s2) (60 kg)(1.67 m/s2) (60 kg)(25.9 m/s2) 588 N 100 N 1552 N
  26. 26. Weightlessness “less” gravity  NOT no gravity
  27. 27. Newton & Gravity  1687  Principia “Every object in the  universe is attracted to and attracts every other object in the universe by a force called gravity”
  28. 28. Gravitational Force  Mutually attractive force  Inverse square GM1M2 r2 where G  Fg = = 6.67 x 10-11Nm2/kg2
  29. 29. g on Uranus? Fg = m x g = GM1M2/r2  G Mplanet g = rplanet2 (6.67 x 10-11 Nm2/kg2)(8.44 x 1025 kg) g =(2.56 x 107 m)2 g = 8.59 m/s2
  30. 30. Size of Gravitational Force (6.67 x 10-11 Nm2/kg2) (60 kg)(60 kg)  Fg = (1 m)2 Fg = 2.4 x 10-7 N 
  31. 31. Size of Gravitational Force (6.67 x 10-11 Nm2/kg2) (6 x 1024 kg)(7.35 x 1022kg) Fg =  (3.83 x 108 m)2 Fg = 2 x 1020 N
  32. 32. Escape Velocity d = 1/2gt2 for objects in free fall  2d = gt2 but t = v/g for free fall 2d/g = t2 = (v/g)2 2 dg = v2 √2dg = v = ESCAPE VELOCITY
  33. 33. Escape Velocity vE = √2dg = √2gREarth = √2(9.8m/s2)(6.378 x 106 m) = 11.18 X 103 m/s
  34. 34. How high will it go? V2 = 2dg V2/2g = d (10 m/s)2 2 (9.8 m/s2) =d d = 5.1 m
  35. 35. Newton’s Laws of Motion In the absence of outside  forces, the total momentum of a set of objects remains the same no matter how the objects interact with one another. p=mv 
  36. 36. Conservation of Momentum m vbefore = m vafter  (3000 kg)(10m/s) + (1000 kg)(0 m/s) = (3000 kg)v’ + (1000 kg) (15 m/s) 30,000 kg m/s = (3000 kg) v’ + 15,000 kg m/s 15,000 kg m/s = (3000 kg) v’ -------> v’ = 5 m/s
  37. 37. Conservation of Momentum m vbefore = m vafter  (2000 kg) (8 m/s) + (50 kg) (0 m/s) = (2000 + 50 kg) v’ 16,000 kg m/s ÷ 2050 kg = v’ = 7.8 m/s
  38. 38. Inelastic Collisions (2 kg)(10 m/s) 3 kg v’ =? v = 0 m/s
  39. 39. Elastic Collisions (2 kg)(10 m/s) 3 kg v’ =? v = -2 m/s
  40. 40. Angular Momentum m1 x v1 x r1 = m2 x v2 x r2 
  41. 41. Circular Motion 2 r = diameter  2πr = circumference  Magnitude of v doesn’t  change but direction does
  42. 42. Centripetal Acceleration v a= t  vt - vb = 1/2(2 r)/v 2v = r/v v2 mv2 ac = rFc = r
  43. 43. Applications Spin cycle  washer
  44. 44. Car turning
  45. 45. The ROTOR
  46. 46. Centripetal Force mball = 0.25 kg r = 0.5 m v = 2 m/s Fc = ?
  47. 47. Centripetal Force mball = 0.25 kg r = 0.5 m v = 2 m/s (0.25 kg)(2 m/s)2 Fc = 0.5 m = 2 Newtons
  48. 48. Roller Coaster Loop Fc> Fg  mv2 r > mg V2/r > g
  49. 49. Conservation of Energy The Energy of the Universe  Is neither created nor destroyed; It merely changes form.
  50. 50. Forms of Energy
  51. 51. Work and Power W=Fxd  work Power = time 
  52. 52. Work W=Fxd  W=mxgxd  W = (50 kg)(9.8m/s2)(5m)  = 2450 kg m2/s2 = 2450 Joules
  53. 53. Power Work  Power = time 2450 J = 30 s = 81.67 J/s = 81.67 Watts
  54. 54. Kinetic Energy Work = F x d = (m x a) x d If d = 1/2at2 and v = at then d = 1/2a(v/a)2 = 1/2v2/a W = m a d = m a (1/2 av2/a) = 1/2mv2
  55. 55. Potential Energy Potential Energy = m x g x h
  56. 56. Potential & Kinetic Energy  PE + KE = Total Energy  PEtop = KEbottom mgh = 1/2mv2  2gh = v2  V = √2gh 
  57. 57. Escape Velocity vE = √2dg = √2gREarth = √2(9.8m/s2)(6.378 x 106 m) = 11.18 X 103 m/s
  58. 58. Terminal Velocity 1 Kg book falls 1 meter vf = ? V = √2gh = √2(9.8m/s2)(1m) = √19.6 m2/s2 = 4.4 m/s
  59. 59. How tall is the incline? V = 5.42 m/s  V = √2gh  Thus h = v2/2g = (5.42 m/s)2/2(9.8 m/s2) = 1.5 m
  60. 60. Roller Coaster
  61. 61. Pole Vault World Record = 6 m  V = √2gh  = √2 (9.8m/s2)(6 m) = 10.9 m/s
  62. 62. Heat transfer Heat:  Energy transferred between 2 systems in contact and at different temperatures
  63. 63. Temperature Average kinetic energy  of atoms or molecules
  64. 64. Temperature scales
  65. 65. Biological Temperature Regulation Human: 37 C = 98.6 F  Shivering, flushing 
  66. 66. Biological Temperature Regulation Birds  Animal fat layer 
  67. 67. Specific Heat The Amount of heat  energy necessary to raise the temperature of a given substance
  68. 68. Heat Energy Heat Energy Q Q=mC T C in units of Joules/g °C or calories/g °C
  69. 69. Heat Capacity C
  70. 70. Calories 1 calorie: amount of heat needed to raise temp of 1.0 gram H2O 1° C
  71. 71. Dietary Calories 1 Calorie = 1000 calories 100 Calories 100,000 calories!
  72. 72. Calorie burning
  73. 73. Heat Transfer Wooden vs. Aluminum  Each pot contains 500 cal. Each spoon 100 g How hot will each one get?
  74. 74. Heat Transfer  Aluminum spoon Q = mC T = 500 cal = (100g)(0.22cal/gºC) T 500 cal T = (100g) (0.22cal/gºC) = 22.73°C
  75. 75. Heat Transfer  Wooden spoon Q = mC T = 500 cal = (100g)(0.58cal/gºC) T 500 cal T = (100g) (0.58cal/gºC) = 8.82°C
  76. 76. Identifying Unknowns  A 400 g metal w/3680 Joules of Heat Temp 50°C -> 60°C What is C? Q C=m T = 3680 J/400g (10°C) = 0.92 J/g °C
  77. 77. Limiting Heat Transfer Cair = 0.17 cal/g°C 
  78. 78. Refrigeration
  79. 79. Sound Energy Result of Vibrations  Air molecules disturbed  Ear membrane vibration  Auditory nerve -> Brain 
  80. 80. Hearing
  81. 81. Cochlea
  82. 82. Waves
  83. 83.  Wavelength: distance between crests( )  Frequency: # crests pass a given pt/time (f)  x f = velocity of sound (m) (1/sec) 1/sec = HERTZ
  84. 84. Infrasound f of elephant communication  if is 34 m? fx = vs = 340 m/s vs Thus f = = 10 1/s = 10 Hz
  85. 85. Ultrasound f of dolphin communication  if is 0.0034 m? fx = vs = 340 m/s vs = 105 Hz Thus f =
  86. 86. Audible Sound Waves  Hearing range for normal human: 20 - 20,000 Hz  S,z,c sounds vs.  M,b sounds
  87. 87. Sound & Medium Velocity of sound in different media 0º C air 331 m/s Helium gas 970 m/s Fresh water 1493 m/s Salt water 1513 m/s Granite 6000 m/s
  88. 88. Sound & Temperature  vs = vo + (0.61 m/sºC)T
  89. 89. Hot Day vs. Cold Day 110° F vs. –30 ° F?  At 110° F = 43.33 °C vs = 331 m/s + (0.61m/s °C) (43.3 °C) = 357.43 m/s At –30 ° F = –34.4 ° C vs = 331 m/s + (0.61m/s °C) (–34.4 ° C) = 310 m/s
  90. 90. Echolocation Bat sends signal and  receives echo 0.7 s later in 4° C cave -- how far is the wall? vs = 331 m/s + (0.61m/s °C) (4°C) =333.4m/s d = v x t = vs x t/2 = (333.4m/s)(0.35s) =116.7 m
  91. 91. Sound Intensity Bel = 10 db  intensity doubling (d2)2 I1 (d1)2 = I2 2 Intensity drops with (distance)
  92. 92. Sound Intensity
  93. 93. Intensity comparison  Standing 2 m vs. 200 m from jet taking off? (200m)2 120 db (2 m)2 x 40000/4 = 105 = 5 factors of 10 x = 70 db
  94. 94. Doppler Effect
  95. 95. Doppler Effect  Approaching sound f Vs f’ = f VS - V  Retreating sounds f Vs f’ = f VS + V
  96. 96. Doppler Example Approaching at 30m/s: 340m/s f’ = (440 Hz) 340 - 30 m/s = 483 Hz Retreating at 30 m/s: 340m/s f’ = (440 Hz) 340 + 30 m/s = 404 Hz
  97. 97. Medical Doppler Blood flow velocity  F= 80000 Hz, f’ = 80020 Hz f’ vs 1500 m/s f = vs - v = 1.00025 = 1500 - v m/s => v = 0.375 m/s = 37.5 cm/s
  98. 98. Sonic Boom
  99. 99. Music Pythagoras   Octave = 2 f  Harmonious frequencies = simpler ratio

×