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Published byEthel Price Modified over 9 years ago
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Motion, Forces, and Energy Chapter 1: Motion
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Recognizing Motion: Motion: –When an object’s distance changes relative to a frame of reference Frame of Reference: –A fixed point from which distance is measured –Ex. Tree
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Measuring Distance: Measured using the SI (Systeme International) System Meter (m): basic SI unit. 1 m = 100 cm = 1000 mm = 1/1000th km
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Metric Conversion The Stair Step Method
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Calculating Speed: Speed: –Distance traveled in a given amount of time S=distance/time
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Describing Velocity Velocity: –The speed AND direction of an object or the speed in a particular direction Calculating velocity: V = d/t; and a direction
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Acceleration: The rate of change of velocity; or how quickly an object speeds up, slows down, or changes direction.
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Calculating Acceleration: A = Final velocity – Initial Velocity Time A = (V F – V I ) / T Units are: m/s 2
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Chapter 1 Test MOTION SPEED VELOCITY GRAPHING MOTION ACCELERATION
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Motion, Forces, and Energy Chapter 4: Work and Machines
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What is Work? Work is done when force is applied and an object moves Work = Force X Distance (when Force is in Newtons and Distance is in Meters; Nm) 1.0 Nm = 1.0 Joule (J)
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Simple Machines Devices designed to –Make work easier –Change the distance over which a force is applied –Change the direction of the applied force
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6 Simple Machines 1. Inclined Plane: –A slanted surface used to raise an object 2. Wedge: –A device thick on one side and very thin on the other 3. Screw: –An inclined plane wrapped around a cylinder
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6 Simple Machines Con’t 4. Lever: –A rigid bar free to pivot around a fixed point (fulcrum) 5. Wheel and Axle: –Two cylinders that are fixed together and rotate around a common axis 6. Pulley: –A grooved wheel with a chain, rope, or cable wrapped around it
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Mechanical Advantage Definition: The number of times a machine multiplies your force. Ideal M.A. = The mechanical advantage without friction.
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M.A. for a Lever M.A.= Length of effort arm Length of resistance arm NO UNITS!
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M.A. for a Wheel and Axle M.A.= Radius of wheel Radius of axle NO UNIT!
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M.A. for an Incline Plane M.A.= Length of incline height of incline NO UNIT!
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M.A. for a Pulley System Count the number of weight holding ropes. That’s the mechanical advantage.
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Efficiency Definition: The work output of a machine compared to the work input. Calculation: E= work output work input X 100
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