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REVIEW FOR THE NYS Regents Physical Setting / Physics Exam

REVIEW FOR THE NYS Regents Physical Setting / Physics Exam. Adriana Gheta. General Exam Content. Mechanics Energy Electricity/Magnetism Waves/Light Modern Physics. ~ 35%. ~ 12%. ~ 23%. ~ 21%. ~ 9%. Exam Struture :.

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REVIEW FOR THE NYS Regents Physical Setting / Physics Exam

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  1. REVIEW FOR THE NYS Regents Physical Setting / Physics Exam Adriana Gheta
  2. GeneralExam Content Mechanics Energy Electricity/Magnetism Waves/Light Modern Physics ~ 35% ~ 12% ~ 23% ~ 21% ~ 9%
  3. Exam Struture: Part A – Multiple choice. Usually 35 questions, or 41% of the exam. Part B1 – Multiple choice. Usually 12 – 15 questions, or about 14 – 18% of the exam. ~47-51 Multiple choice questions Part B2 – Some multiple choice, mostly constructed-response questions. Usually accounts for 15 – 20% of the exam Part C – Extended/constructed response. Usually 20 credits, or 24% of the exam. ~ 25-30 Extended constructive response
  4. EveryQuestionisImportant! Total number of points possible (Raw Score):85 Multiple choice question points: 50 That’s as much as60%of the raw score!
  5. DO NOT RUSH TROUGH THE MULTIPLE CHOICE! Treat Multiple choice questions like word problems (they usually are), and take the time to solve them properly. You’ll have scratch paper – USE IT! RTQ! Read the questions carefully to make sure you are answering properly! Don’t leave ANY blank!
  6. Seek Assistance whenever necessary!
  7. Use the Problem Solving Method! Step 1: Read the problem! Identify all givenorimplied pieces of information , and everything the problem is asking for . Write it/them down using appropriate symbols. Implied data: Starting from rest Falling Vi = 0 Coming to a stop Vf = 0 Asking for displacement, velocity or any force Answer must contain a number and direction (-, +, N, S, W, E) Vertical motion g = - 9.81 m/s2 V = 0 or V = constant Newton’s 1st law: Fnet = 0 Equilibrium V = 331 m/s Sound Electromagnetic waves C = 3 x 108 m/s
  8. Step 2: Write down the equation(s) that will help you solve the problem, and algebraically solve for the desired variable (you might not like to do this, but you won’t make as many math errors, and you’re more likely to have the correct units on your answer)! Step 3: Substitute the appropriate numbers, with the appropriate units into the equation at least one time. Step 4: Perform the calculation, then be sure to write the correct answer with the correct units!
  9. Example 6.1 x 10-7 m
  10. Vectors
  11. Scalars vs. Vectors Scalars : Magnitude only Examples of Scalar quantities : distance, speed, time, energy (work), power Vectors: Magnitude and Direction Examples of Vectors quantities : Displacement, velocity, acceleration, force, momentum, impulse
  12. Vector addition Head – to - tail θ Scalars (ex: work): d1 + d2 Vectors (ex: force) : (Pythagorean theorem) θ East of North Scalars (ex: distance): d1 + d2 Vectors (ex: displacement) : (d1 + d2) North Scalars (ex: speed): d1 + d2 Vectors (ex: velocity) : (d1 – d2) South The BIGGERthe angle the SMALLER the resultant
  13. Equilibrant The equilibrant force is equal in magnitude but opposite in direction to the resultant vector. R E
  14. Sample problems A child walks 5.0 meters north, then 4.0 meters east, and finally 2.0 meters south. What is the magnitude of the resultant displacement of the child after the entire walk? 5 m The resultant of a 12 N force and a 5 N force is 7 N. What is the angle between forces? 1800 Which pair of concurrent forces may have a resultant of 20 N? a) 5 N and 10 N b) 20 N and 50 N c) 20 N and 20 N d) 30 N and 5 N (c) What is the equilibrant of three concurrent forces: 5 N due West, 10 N due East and 10 N due North. a) 5 N due East b) 11.2 N due NE c) 11.2 N due SW d) 5N due West (c)
  15. Vector Components When object is on horizontal surface Vy F V Fy θ Fx Vx Ay = A sin θ Ax = A cosθ Fy = F sin θ Fx = F cosθ Vy = V sin θ Vx = V cosθ θ = tan Vy/Vx
  16. Vector ComponentsWhen object is on an incline surface FII Fperp θ θ Fg Ay = A sin θ Ax = A cosθ A┴ = A cosθ AII = A sin θ
  17. Sample problems Mathematically determine the horizontal and vertical components of a 50 N force at 300. 43 N; 25 N (3)
  18. Distance vs. Displacement A man walks 10 m east and then 5 m north. How much distance did he traveled? b) What is his displacement from the starting point? 15 m 11.2 m 270 north of east
  19. Linear Motion
  20. Linear Motion Equations! v = vf + vi 2 Dv = vf - vi Don’t Forget! You will need these also! (memorize!)
  21. Practice Problem # 1Constant velocity motion (1) 2.5 m/s
  22. Practice Problem # 2Horizontal acceleration The speed of an object undergoing constant acceleration increases from 8.0 m/s to 16 m/s in 10 s. How far does the object travels during the 10s? (1) 3.6 x 102 m (3) 1.2 x 102 m (2) 1.6 x 102 m (4) 8.0 x 102 m (3) 1.2 x 102 m
  23. Practice Problem # 3Drop problem 2. A rock falls from rest a vertical distance of 0.72 m to the surface of a planet in 0.63 s. The magnitude of the acceleration due to gravity on the planet is: (1) 1.1 m/s2 (3) 3.6 m/s2 (2) 2.3 m/s2 (4) 9.8 m/s2 (3) 3.6 m/s2
  24. Practice Problem # 4Thrown downward problem A ball is thrown straight downward with a speed of 0.50 m/s from a height of 4.0 m. What is the speed of the ball 0.70 s after it is released? (Neglect friction.) (1) 0.50m/s (3) 9.8 m/s (2) 7.4m/s (4) 15 m/s (2) 7.4 m/s
  25. Practice Problem # 5Acceleration due to gravity A 1.0 kg ball is dropped from the roof of a building 40 m tall. What is the ball’s time of fall? (Neglect friction) (1) 2.9 s (3) 4.1 s (2) 2.0 s (4) 8.2 sm (1) 2.9 s
  26. Graphs
  27. THREE QUESTIONS TO ASK YOURSELF: Q1: What is the slope? Q2: Is the slope constant (straight line) or variable (curved line)? Q3: What is the area under the graph, if it represents a physical quantity?
  28. Distance vs. Time d d d t t t Slope? Type of motion?
  29. Velocity vs. Time v v t t Slope? Type of motion? Area under the graph? Area: Distance
  30. Practice Problem Which graph best represents the relationship between the acceleration of an object falling freely near the surface of Earth and the time that it falls? a a a a t t t t (2) (4) (1) (3) (4)
  31. Practice Problem Which graph best represents the motion of an object in equilibrium? (1)
  32. Practice Problem (4)
  33. Two dimensional motion (projectile motion)
  34. Projectile motion consists of 2 motions: Horizontal motion Constant velocity Accelerated Vertical motion
  35. Horizontal projectile Vx Vy = 0 Vx Fnet g Vy Fnet g Vx Vy Fnet g What would be the new path of the projectile if the air friction is considered?
  36. Practice problem An object is thrown horizontally off a cliff with an initial velocity of 5.0 m/s. The object strikes the ground 3.0 s later. What is the vertical speed of the object as it reaches the ground? (1) 130 m/s (3) 15 m/s (2) 29 m/s (4) 5.0 m/s (2) b. How far from the base of the cliff will the object strike the ground? (1) 2.9 m (3) 15 m (2) 9.8 m (4) 44 m (3)
  37. Projectile from an angle Vx Vy=0 Vy Vx Vx Vy Vx Vy Vx Vy How does the total horizontal distance traveled by the projectile change as the launch angle is increased from 300 to 450? How does the maximum altitude of the projectile change as the launch angle is increased from 300 to 450?
  38. Practice problem A child kicks a ball with an initial velocity of 8.5 m/s at an angle of 350 with the horizontal. The ball has an initial vertical velocity of 4.9 m/s and a total time of flight is 1.0 s. What is the horizontal component of the ball ‘s initial velocity? (1) 3.6 m/s (3) 7.0 m/s (2) 4.9 m/s (4) 13 m/s (3) b. The maximum height reached by the ball is (1) 1.2 m (3) 4.9 m (2) 2.5 m (4) 8.5 m (1)
  39. Forces
  40. Newton’s 1st Law of MotionLaw of inertia Mass and inertia are the same thing. F net = 0 (ΣF = 0) (object at equilibrium) V = 0 or V = ct and a = 0
  41. Practice Problem Which cart has the greatest inertia? A 1-kg cart traveling at 4 m/s A2-kg cart traveling at 3 m/s A 3-kg cart traveling at 2 m/s A 4-kg cart traveling at 1 m/s 1
  42. (2)
  43. Newton’s 2nd Law of MotionF = ma F net = ma (ΣF = ma) (F net is an unbalanced force; object not in equilibrium) Unit for force: Newton (N) 1N = kg m/s2 MASS (m) is not WEIGHT (Fg) Reference Table: Fg = mg
  44. Practice problem A 2 kg box on a horizontal frictionless surface is acted upon by a 9 N horizontal force to the left and a 1N horizontal force to the right. The acceleration of the box is: 5 m/s2 to the right 5 m/s2 to the left 4 m/s2 to the right 4 m/s2 to the left (4)
  45. Practice problem Two forces, F1 and F2, are applied to a block on a frictionless, horizontal surface as shown below. What is the mass of the object if the acceleration is 2 m/s2? F2 = 2 N F1 = 12 N (2) 1 kg 5 kg 6 kg 7 kg
  46. Force of friction The force of friction is always opposite to the motion. When the object is sliding at constant velocity V = ct Ff Fa Fnet = 0  Ff = Fa When the object is sliding with accelerate motion: a Ff Fa Fnet = ma  Fa-Ff = ma
  47. Practice Problem The diagram below shows a 4 kg object accelerating at 10 m/s2 on a rough horizontal surface. Ff Fa = 50 N What is the the frictional force Ff acting on the object. 10 N to the left
  48. Force of friction If the problem mentions the type of materials, you KNOW the coefficient of friction μ Ff = μ FN μs >μk
  49. How to calculate FN FN FN FII Fperp θ Fg θ Fg FN = F┴ = F cosθ FN = Fg As θ Ff 
  50. Practice problem A force of 60 N is applied to a rope to pull a sled across a horizontal force at a constant velocity. The rope is at an angle of 300 above the horizontal. Calculate the magnitude of the component of the 60 N force that is parallel to the horizontal surface. Determine the magnitude of the frictional force acting on the sled. 52 N 52 N
  51. Practice problem A 10 kg wooden object is being pushed across a wooden table. A 100 N force is applied to the box. Determine: Determine the force of friction acting on the object. Determine the net force acting on the object. Determine the acceleration experienced by the box. 29.4 N 70.6 N 7.1 m/s2
  52. Practice problem 780 N
  53. Momentum/Impulse
  54. Momentum P = mv Lower case p= momentum Capital P = power
  55. Impulse Reference Table: J = Ft J = Fnett = Δp Fnett = mΔv
  56. Practice problem A 2 kg laboratory cart is sliding across a horizontal frictionless surface at a constant velocity of 4.0 m/s east. What is the cart’s velocity after a 6.0 N force to the west acts on it for 2.0 s? 2.0 m/s east (3) 10 m/s east 2.0 m/s west (4) 10 m/s west (2)
  57. Practice problem A 0.40 kg ball was thrown with a speed of 20 m/s by a 50 kg student. What was the magnitude of the impulse imparted to the ball by the student? 8.0 Ns (3) 4.0 x 102 Ns 78.0 Ns (4) 1.0 x 102 Ns (1)
  58. Conservation of momentum Momentum is conserved in all collision systems. p before = pafter Reference Table: m1v1 + m2v2 = m1v1’ + m2v2’ Explosion: 0 = m1v1’ + m2v2’ Inelastic collision: m1v1 + m2v2 = (m1 + m2)v’ Elastic collision: m1v1 + m2v2 = m1v1’ + m2v2’
  59. Practice problem (4)
  60. Practice problem (3)
  61. A 3.11 kg gun initially at rest is free to move. When a 0.015 kg bullet leaves the gun with a speed of 500 m/s, what is the speed of the gun? 2.4 m/s 2.4 m/s
  62. Work/Energy Power
  63. Vertical W = Δ PE Horizontal W = Δ KE KE increases as velocity increases. PE increases as height increases. Total mechanical energy remains the same. Units: Joules J = N · s or J = kg m2/s2
  64. Practice problem A child applies a constant 20 N force along the handle of a wagon which makes a 250 angle with the horizontal. 20 N 250 How much work does the child do in moving the wagon a horizontal distance of 4 m? 5.0 J (3) 73 J 34 J (4) 80 J (3)
  65. Practice Problem A 5 N force causes a spring to stretch 0.2 m. What is the potential energy stored in the stretched spring? ` 0.5 J What is the spring’s constant? 25 N/m
  66. Law of Conservation of energy Mechanical energy is the sum of the potential and kinetic energy. (Q is the internal energy or work done by friction (heat)) Mechanical energy does not change for a free falling mass or a swinging pendulum, if friction is not present (closed system).
  67. Practice (2)
  68. Practice Problem (2)
  69. Practice Problem A pendulum of mass 2 kg oscillates between points A, B, and C, where B is the lowest point. If the pendulum has 36 J of energy while at point B, what is the height from which the pendulum is dropped. 1.8 m
  70. Circular Motion
  71. V Fc ac
  72. Practice Problem A car travels at constant speed around a horizontal, circular track, moving in a counterclockwise direction. Draw a diagram showing the direction of the velocity vector, acceleration vector and force vector at point A. A If the car has a mass of 1750 kg, and is moving a constant speed of 15 m/s around the curve that has a radius of 45 m, calculate the centripetal force. 8750 N
  73. Law of Gravitational Attraction
  74. Two masses m1 and m2 attract each other with a force F when at 2 m apart. What does the force become when the masses are tripled and the distance is doubled. 2.25 F or 9/4 F Draw a graph showing the relationship between Force and Distance. What is the magnitude of the gravitational force between two electrons separated by a distance of 1.00 x 10-8 meter? 5.5 x 10-55 N What is the magnitude of the electrostatic force between two electrons separated by a distance of 1.00 x 10-8 meter? 2.3 x 10 -12 N
  75. Static Electricity
  76. Charging objects with static electricity: Conduction (contact) same charge Induction (from distance)  opposite charge E is a vector. Direction (positive test charge) and magnitude. Electric field has energy (W = V x q) Units of energy: J and eV
  77. Direction of the field E around a positively charged particle
  78. Direction of the field E around a negatively charged particle
  79. DIPOLES Electric field around 2 charges of opposite sign
  80. Electric field around 2 charges of the same sign The field is zero half away between the two charges
  81. Parallel plate capacitor Electric field between the plates is uniform. Equal strength throughout.
  82. 2
  83. A metal sphere has a negative charge of 1.1 x 10-6 C. Approximately how many more electrons than protons are on the sphere? 6.9x 10+12 Calculate the electrostatic force of attraction between the proton and the electron in the atom of hydrogen, at a distance on 1 nm apart. 2.3 x 10-10 N Calculate the gravitation force of attraction between the proton and the electron in the atom of hydrogen, at a distance on 1 nm apart. 1.0 x 10-49 N
  84. Two metal spheres having charges of +4.0X10-6 coulomb and +2.0X10-5 coulomb, respectively, Are brought into contact and then separated. After separation, the charge on each sphere is: 1) 8.0X10-11 C 2) 8.0X10-6 C 3) 2.1X10-6 C 4) 1.2X10-5C 4 2
  85. Electric Current
  86. What is the resistance at 200 C of a 2.0 m length of tungsten wire, with a cross section area of 7.9 x 10 -7 m2 1.4 x 10-1Ω A charge of 30 C passes through a 24 ohm resistor in 6.0 seconds. What is the current through the resistor? 5A An electric heater operating at 120 V draws 8.00 A of current through its 15.0 ohms of resistance. What is the total amount of heat energy produced by the heater in 60.0 seconds. 5.76 x 104 J
  87. The electrical resistance of a metallic conductor is inversely proportional to its: 1. Temperature 2. Length 3. Cross-sect area 4. resistivity 3
  88. Electric circuits Ammeters: connected in series Voltmeters: connected in parallel Adding a resistor in parallel decreases the total resistance of the circuit, and increases the current. (need for a fuse) Adding a resistor in series increases the total resistance of the circuit, and decreases the current.
  89. Series circuit Req>biggest resistance Parallel circuit Req<smallest resistance
  90. 3
  91. A simple circuit consists of 100 ohm resistor connected to a battery. A 25 ohm resistor is to be connected in the circuit. Determine the smallest equivalent resistance possible when both resistors are connected to the battery. 20 ohms
  92. Magnetism
  93. The direction of magnetic field is define by the direction of a compass needle. Magnetic field lines point from N  S outside the magnet, and S  N inside the magnet. (they are closed lines) The strength of the magnetic field is shown by the density of field lines per unit area.
  94. The diagram below shows a bar magnet. Which arrow best represents the direction of the needle of a compass placed at A. A N S (1) ↑ (2) ↓ (3) → (4) ← (3) →
  95. 1
  96. Waves
  97. Mechanical waves (they need a medium) Transversal waves Longitudinal waves (SOUND) Electromagnetic waves (Light) ( no medium) (light waves are transverse) E E Blue has more energy than red. The speed of all types of electromagnetic waves is the speed of light 3.0 x 108 m/s The speed of sound: 331 m/s
  98. Amplitudeof a waves determine its energy: amplitude in sound: amplitude in light : loudness brightness Frequency in waves: Frequency in sound: Frequency in light: pitch color
  99. 2
  100. 3 m 60 m/s
  101. (2)
  102. 1. Interference (Standing waves) a. Constructive (in phase or O0) b. Destructive (out of phase or 1800) Wave Phenomena 2. Doppler effect (change in f due to relative motion of the source and the observer). http://www.astro.ubc.ca/~scharein/a311/Sim/doppler/Doppler.html 3. Resonance

  103. Wave phenomena

  104. Wave phenomena

    Reflection
  105. 4. Reflection: a. Regular reflection (mirror-like reflection) b. Diffuse reflection Law of reflection: Angles must be measured to the normal.

  106. Wave phenomena

  107. Wave phenomena

    Refraction

  108. Wave phenomena

  109. From less dense into a denser: Light slows down, bends towards the normal and has a shorter wavelength n1 n1 n2 n2 From denser into a less dense: Light speeds up, bends away from the normal and has a longer wavelength

  110. Wave phenomena

  111. Wave phenomena

  112. Wave phenomena

    Dispersion

  113. Wave phenomena

    Diffraction

  114. Wave phenomena

  115. Wave phenomena

  116. Absolute index of refraction 5. Refracton: a. Snell’s Law Relative index of refraction 6. Diffraction: bending due to an opening (opening diffraction) Angles must be measured to the normal.
  117. (1)
  118. Modern Physics
  119. Energy is quantized (Comes in definite amounts, called photons) Photon = quantum of electromagnetic radiation How do we calculate the energy of a photon? Calculate the energy in Joules and eV of a photon of red light with wavelength of 700 nm. E = 2.84 x 10-19 J = 1.8 eV The energy of a photon is 2.11 eV. Determine the wavelength of the photon Determine the color of the light associated with the photon. 3.38 x 10-19 J 5.89x10-7 m yellow
  120. All photons in a vacuum have the same: Wavelength Frequency Speed Energy 3 The energy of a photon is inversely proportional to its: Phase Speed Wavelength Frequency 3 Explain why a hydrogen atom in the ground state can absorb a 10.2 eV photon, but cannot absorb an 11.0 eV photon.
  121. Photons Do NOT have MASS Experiments: 1) Photoelectric effect (shows photons have KE) (shows photons have momentum) 2) Compton’s effect Wave particle duality: Light acts like both, waves and particles. Particle behaviors Waves behaviors Reflection Diffraction Interference Refraction Doppler effect Photoelectric effect Compton’s effect
  122. Light demonstrates the characteristics Particle only Waves only Both particles and waves Neither particles nor waves 3 Which phenomenon can best be explained by the wave model of light rather than the particle model of light? 1. Interference 2. reflection 3. energy transfer 4. photoelectric effect 1
  123. Which phenomenon can be explained by both the particle model and wave model? Reflection Polarization Diffraction Interference 1 A variable-frequency light source emits a series of photons. As the frequency of the photon increases, what happens to the energy and wavelength of the photon? The energy increases and the wavelength increases The energy decreases and the wavelength increases The energy decreases and the wavelength decreases The energy increases and the wavelength decreases 4
  124. Compared to a photon of red light, a photon of blue light has a Lower frequency Smaller momentum Greater energy Longer wavelenght 3 When incident on a given phootemissive surface, which color of light willl produce photoelectrons with the greatest energy? Orange Green Violet Red 3 In which part of the electromagnetic spectrum does a photon have the greatest energy? Infrared Violet Ultraviolet Red 3
  125. Models of atoms: Rutherford (Gold foil experiment) (alpha particles) Bohr’s model of the atom of H
  126. Compare to a proton, an alpha particle has: The same mass, and twice the charge Twice the mass, and the same charge Twice the mass, and four times the charge Four times the mass, and twice the charge 4
  127. Balmer series Absorption spectrum of hydrogen Emission spectrum of hydrogen
  128. Calculate the amount of energy given off by an electron falling from level 3 to level 2 in the Hydrogen atom. What part of the electromagnetic spectrum is the energy released in? E = 1.89 ev = 3.02 x 10-19 J f = 4.56 x 1014 Hz (red) What is the ionization energy for an electron in the level two of energy in the atom of Mercury, in electronvolts and Joules? E = - 5.74 ev =- 9.2 x 10-19 J 8.82 eV 1.41 x 10-18 J
  129. Nuclear Physics
  130. Fundamental forces Atomic forces Nuclear forces Gravitational force Weak force Electrostatic force Strong force Gravitons Photons Gluons Bosons Which particle has mass and charge?
  131. A helium atom consists of two protons, two electrons, and two neutrons. In the helium atom, the strong force is a fundamental interaction between the Electrons only Electrons and protons Neutrons and electrons Neutrons and protons 4 What type of nuclear force holds the protons and neutrons in an atom together? Strong force that acts over a short range Strong force that acts over a long range Weak force that acts over a short range Weak force that acts over a long range. 1
  132. The chart below lists the rest masses of two particles and a nucleus in atomic mass units What is the mass defect of a 63 Li nucleus? 0.0345 u 0.0615 u 3.0606 u 3.9975 u 1
  133. E = mc2 1. Particle annihilation Particle + antiparticle  photon 2. Pair production Photon Particle + antiparticle
  134. If a proton were combine with an antiproton, they would annihilate each other and become energy. Calculate the amount of energy that would be released by this annihilation. 3.01 x 10-10 J
  135. Standard model Nuclear forces are strong and short ranged.
  136. (4) (2)
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