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Published byHenry Tucker Modified over 9 years ago
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Mid year review
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Format Part 1: – Multiple Choice : 33 questions (4 points each) Part 2: – Short Answer: 15 questions (4 points each)
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Topics Earth and Space – Lithosphere: Ore vs. Mineral (1)
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Lithosphere
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Minerals vs. Ore MineralOre
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Environmental Effects of mining Deforestation Destruction of habitat
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Pollution Heavy Machinery
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Topics Material World: – Chemical Changes Oxidation (1) Combustion (4) – Electricity Charges (4) Static Electricity (2) Electricity formulas (9) Circuit Design (5)
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Changes
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Changes (5) Combustion – Visible signs of rapid combustion – Fire triangle Oxidation – Identify an Oxidation reaction
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Types of chemical changes Oxidation: – Definition: Chemical change that occurs when a substance reacts with oxygen (O 2 ) – Examples Rusting An apple turning brown – Particle Model
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Types of chemical changes Combustion: – Type of oxidation reaction that releases a large amount of energy (light and heat) – Examples Fire – Fire Triangle
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Combustion Triangle
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Electricity
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Elementary particles ProtonsPositive ElectronsNegative NeutronsNeutral
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What does this mean… An element with more electrons than protons will be considered negatively charged A substance with less electrons than protons will be considered positively charged
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How do charges react? Opposites attract, Like charges repel
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Practice Questions
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If I say that by rubbing silk and glass together, the silk gains electrons. Will silk be positively or negatively charged?
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Static electricity 1. Friction 2. Conduction 3. Induction
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Dynamic electricity
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What conducts electricity? – Metals – Graphite – Electrolytes (salts in water)
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Conductivity of a wire – A wire’s conductivity (how much electricity can pass through in a given time) will Increase if the diameter of the wire increases Increases if the length of the wire decreases Increases if the temperature decreases Change with substance used (copper is the best)
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Which of the following plastic
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Circuits
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Circuits (5) Electrical functions Series vs. parallel circuits Draw a circuit Connection of an ammeter and voltmeter Identify the circuit based on description
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Circuitry basics All circuits must have elements that perform the following electrical functions – Power supply: Battery – Conductors:Wires – Transform energy:Resistors, Lights To that you can add – ControlSwitch – ProtectionFuse
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Circuitry Basics Parallel – More than 1 pathway – Independent – Lights controlled separately – More energy efficientSeries – Only 1 pathway – Dependant: 1 goes out they all do – 1 switch controls everything – Less energy efficient
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Drawing a circuit Read the question carefully – Find out whether they are asking for a series or parallel circuit Draw the circuit (1, 2 or 3 boxes) Add the power supply Add and label the necessary components
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Adding Ammeter and Voltmeter An Ammeter – Measures current intensity – Placed directly in the circuit A voltmeter – Measures potential difference – Measures 2 points
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Questions on Circuits A circuit consists of two light bulbs (L1 and L2), a switch, and a power supply. When switch 1 is open L1 stays on and L2 goes out. Close the switch and both lights are on. Draw the circuit
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What are the electrical functions found in the following circuit?
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Formulas
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Formulas (9) Basic Applications – V=RI – E=Pt – P=VI – Qualitative V=RI Dual Equations Find the most energy efficient appliance (calculate E)
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To solve Read the question carefully Underline the important information and highlight what is being asked of you (what should your final answer be) Find the formula that has your missing variable in it. Identify the remaining relevant information in your question. (If you are missing a second variable you need a second formula) Solve the problem Do not forget to include your units
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Calculate the resistance value for each of the following resistors Resistor – A2 V10 A – B5 V3A – C3 V20A – D6 V2A
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Question – While having breakfast, you notice the following information on the specification plate of the toaster. – You also note that this toaster toasts the bread in 1.5 minutes. What quantity of electrical energy is consumed by the toaster's element to toast the bread?
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Topics Technological World – Motion transmission and transformation systems (1) – Speed change and torque (3) – Adhesion and friction (1) – Drawing in Multiview (1) – Drawing developments (1) – Tolerances (2) – Electrical functions (5) – Controls (1) – Resistance coding (3) – Constraints and Properties (2) – How something works (2)
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Motion System Transmission and transformation
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Motion Systems Motion Transmission Same type of motion Gear Train Chain and Sprocket Worm and Worm gear Friction gear Belt and pulley Motion Transformation Different types of motion Rack and Pinion Cam and Follower Screw gear systems Slider and Crank
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Speed Change Speed ratio: driver gear driven gear
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Adhesion and Friction Adhesion: – when two objects want to stick together – Better adhesion when: Objects have rough surfaces Objects are warmer No lubricants Friction: force that opposes motion
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TECHNICAL DRAWINGS
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Different Views Multiview A set of 2D drawings Uses normal graph paper Uses all types of lines Isometric A single 3D drawing Uses weird dotted paper Uses only visible lines
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Developments
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Tolerance
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Tolerance Dimensioning Tolerance is the total amount that a specific dimension is permitted to vary; It is the difference between the maximum and the minimum limits for the dimension. For Example a dimension given as 1.625 ±.002 means that the manufactured part may be 1.627 ” or 1.623 ”, or anywhere between these limit dimensions.
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Allowance & Clearance Interchangeable Fit
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Electronics
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Electrical Functions 1. Power supply: – Supplies energy to the circuit – Examples: Battery, power supply, photovoltaic cell 2. Conduction: – Ability to transfer electrons
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Factors that affect conduction Length: – The shorter the wire the better the conductor Diameter – The wider the wire the better the conductor Temperature – The colder the wire the better the conductor Nature of the material – A metal is better than a metalloid (carbon) which is better than a non-metal
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3. Protection: – Element whose goal is to protect the circuit in case of a surcharge
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Electrical functions continued 4. Insulation: – Element whose function is to slow down the electrical current
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p.468
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Electrical Functions 5. Control – Component that has the ability to control the flow of electricity in a circuit – Flip flop switch, lever switch, push button, magnetic switch
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Defining switches UniPolar vs. Bipolar Unidirectional vs Bidirectional
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Electrical Functions 6. Transformation of energy – Any component that has the ability to transform electrical energy into another form of energy (heat, light, magnetism, vibration)
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7. Relay – Function: Element that uses a small amount of power to switch another circuit which requires a larger amount of power
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8. Condenser (Capacitor) – Function: Stores energy Allows to even out current fluctuations Allows to discharge stored energy in one shot (e.g. camera flash)
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9. Diode – Allows the current to flow in only one direction Has low resistance one way, incredibly high resistance the other) Converts Alernating current into direct current
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10. Transistor – Function: Amplifies an electronic signal – Used in computers – binary code
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Materials
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Properties Hardness Resilience Malleability Ductility Stiffness Conductor of heat Conductor of electricity Resists corrosion
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Properties Hardness Resilience Malleability Ductility Stiffness Conductor of heat Conductor of electricity Resists corrosion Wood
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Properties Hardness Resilience Malleability Ductility Stiffness Conductor of heat Conductor of electricity Resists corrosion Ceramic
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Properties Hardness Resilience Malleability Ductility Stiffness Conductor of heat Conductor of electricity Resists corrosion Metal
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