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Motion and Light

Motion and Light. 2010-2011. Jag Mark 1/3/11. Genetics problems from science spot. Jag Mark 1/4/11. Name the Ologist set 1. Jag Mark 1/5/11. Name the Ologist set 3. Jag Mark 1/6/11. Name the Ologist set 4. Jag Mark 1/7/11. Name the Ologist set 5. Jag Mark 1/11/11.

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Motion and Light

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  1. Motion and Light 2010-2011

  2. Jag Mark 1/3/11 Genetics problems from science spot.

  3. Jag Mark 1/4/11 Name the Ologist set 1.

  4. Jag Mark 1/5/11 Name the Ologist set 3.

  5. Jag Mark 1/6/11 Name the Ologist set 4.

  6. Jag Mark 1/7/11 Name the Ologist set 5.

  7. Jag Mark 1/11/11 Sandra conducted a velocity lab in science class. She races a hot wheel car from a starting point on an inclined plane. Her data can be found in the table. Use her data to determine the average speed of the car. Graph her results.

  8. Jag Mark 1/12/11 Tami has been assigned a science project for the science fair. She will be conducting an experiment to determine which teacher gives out the most homework during a nine weeks. Define the controls, independent, and dependent variables for her experiment.

  9. Jag Mark 1/13/11 Draw a sketch of a distance vs time graph of a cyclist riding a bicycle for 200 meters in 45 seconds, then stopping for water for 10 seconds, then riding her bicycle for 500 meters in 2.5 minutes.

  10. Classwork READ pages 86-107 in Green Textbook. Complete guided reading on pages 37-44. (Answers only! READ FIRST!!!)

  11. Jag Mark 1/14/11 Describe the differences between the Lithosphere and the Asthenosphere. Describe the different types of boundaries that exist between tectonic plates.

  12. Jag Mark 1/18/11 Ruby and Max are enjoying a snow day! The are sledding down their favorite hill. If they start at the top of the hill at 0m/s and then accelerate to 40m/s after 4 seconds, what is their rate of acceleration? Label an acceleration graph with the appropriate x and y-axis.

  13. Jag Mark 1/19/11 We are rearranging the science lab. (NOT REALLY…so don’t move any desk!) One student pushes a desk towards the window with a force of 10 N. Mrs. Foles pushes the desk away from the window with a force of 15 N. Draw a force diagram illustrating the forces. What is the magnitude and direction of the net force acting on the desk?

  14. Jag Mark 1/20/11 Describe Newton’s 3 Laws of Motion and give an example of each.

  15. Jag Mark 1/21/11 What is friction? Name 2 ways friction can be reduced and why you would want to decrease friction. Name 2 ways friction can be increased and why you would want to increase friction.

  16. Jag Mark 1/24/11 Draw and label an electromagnetic spectrum illustrating at least 3 electromagnetic waves besides visible light.

  17. Jag Mark 1/25/11 Test Day!

  18. Motion • Motion is a change in position over time. • Motion depends on a reference point which is an object used for comparison with the object in motion. Stationary objects are good reference points. • Position is an object’s location in relation to a reference point.

  19. Reporting Motion • Qualitative: Describing motion • Fast or slow • Quantitative: measuring motion • Speed = Distance Time • Speed = 120 miles 2 hours • Speed = 60 miles/hour

  20. Speed vs Velocity • Velocity is speed plus direction. • Speed = 60 miles/hour • Velocity = 60 miles/hour north • Distance is how far the object traveled. • Time measures how long it took the object to travel the distance.

  21. d t v SPEED Speed is the distance that an object travels in a period of time. Units are meters and seconds However, sometimes km/hr is more sensible. A cyclist travels 25 km in ½ an hour. What is their speed - in kmhr-1 - in ms-1 = 25km/0.5hr = 50km/hr = 25000m/1800s = 13m/s

  22. 1.5 Distance (km) 1 0.5 1 2 3 Time (min) DISTANCE/TIME GRAPHS A car takes 1.5 minutes to travel 500m down a busy road. It stops at lights for 30 seconds, then continues on for 1 minute as it goes another 1km. Plot this on a distance/time graph. Δd = 1km Steepest section is fastest • Using the distance/time graph: • What is the total distance traveled? • 2. In what part of the trip is the car going the fastest? • 3. What is the fastest speed? = 1.5 km Δt = 1min = part 3 v = Δd / Δt v = 1km/1min v = 1000m/60s v = 16m/s In a distance/time graph the slope of the line = the speed of the object.

  23. SPEED QUESTIONS What would these look like on a distance/time graph? 1. stopped 2. slow 3. fast 4. accelerating

  24. Motion on Earth • Theory of Plate Tectonics states that Earth’s plates move slowly in various directions through convection energy transfer in the mantle. (some push away; some push together) • Tectonic plates are large pieces of the lithosphere that are in constant motion. • Some move cm each year; others just mm • Distance=5cm/year x 1000 years=5000cm (50m)

  25. Motion on Earth • Lithosphere is the rocky outer shell of Earth that includes the crust and upper mantle. (brittle and rigid) more solid • Continental Crust: composed of sedimentary, igneous, and metamorphic rocks and make up the continents • Oceanic Crust: more dense, thinner mafic rock layer that makes up ocean basins • The asthenosphere lies just below the lithosphere. It is much hotter with a low density and very ductile. (plastic and flowing) more liquid

  26. Motion on Earth • Plate Boundary: Region where two tectonic plates meet • Transform (fault) boundary: Plates slide side by side. • Convergent boundary: Plates move towards each other. • Divergent boundary: Plates move away from each other.

  27. Oceanic-Continental Convergent: Oceanic plate is more dense and subducts the continental plate creating an ocean trench and a chain of volcanoes.

  28. Continental-Continental Convergent: The two plates collide creating a mountain range.

  29. Oceanic-Oceanic Convergent: collide to create volcanoes and islands in between.

  30. Oceanic-Oceanic Divergent: Forms mid-oceanic ridges leading to underwater volcanoes that give rise to volcanic islands.

  31. Continental-Continental Divergent: Produce rift valleys eventually creating oceanic plates.

  32. Motion on Earth

  33. Acceleration • Acceleration is the rate of change in speed, direction, or both. • Riding your bike at 2 km/h, you slow down to 1 km/h, and then increase speed to 1.5 km/h. (Each time you are accelerating) • acceleration = velocity final - velocityinitial time

  34. Δv a Δt ACCELERATION Acceleration is the change in speed in an object in a period of time. Units ms2 It takes a cyclist 20 secondsto go from a standing start to 14m/s. What is their acceleration? What is 14m/s in km/hr? a = Δv/Δt a = 14m/s / 20s a = 0.7ms2 = 14 × 60s × 60min  1000m = 50.4km/hr

  35. SPEED/TIME GRAPHS Speed (m/s) 8 4 10 20 30 Time (sec) A runner travels at 4m/s for 10 seconds, then stops suddenly for 5 seconds, then accelerates for 5 seconds to get to 8m/s and continues for 10 seconds. Plot this on a speed/time graph. Using the speed/time graph: In what part of the trip is the runner going the fastest? What is the acceleration in part 4? = part 5 In a speed/time graph the slope of the line = the acceleration of the object. a = Δv/Δt a = 8m/s/5s a = 1.6ms2

  36. ACCELERATION QUESTIONS What would these look like on a speed/time graph? 1. stopped 2. slow 3. fast 4. accelerating

  37. SPEED/TIME GRAPHS Speed (m/s) 8 4 10 20 30 Time (sec) In a speed/time graph the distance covered = the area under the graph. Part 2 Part 3 What distance is covered in part 1? What is the total distance covered? d = v × t d = 4m/s × 10s d = 40 m Part 4 Part 1 Part 1 = 40m Part 2 = 0m Part 3 = v × t ×  = 8m/s × 5s ×  = 20m Part 4 = v × t = 8m/s × 10 s = 80m Total = 40 + 20 + 80 =140m

  38. FORCES Forces are pushes or pulls (a combination is a twist).   Objects are stationary when forces are balanced gravity is always acting but we don’t keep falling due to a support force Forces can be measured using a Newton meter.

  39. BALANCED FORCES An unbalanced forces cause changes to objects motion (speed or direction), or shape. If a force acts on a stationary object and causes motion, the object has gained kinetic (movement) energy. Friction will stop the object moving. Types of force: Gravity Friction – the force that opposes motion Magnetism Tension – the force in rope, etc Electrostatic Support Lift – in the air (planes/birds) Buoyancy – in the water

  40. FORCE PAIRS Forces act in pairs (e.g. thrust and friction, gravity and support). Force diagrams show the forces acting on an object and whether they are balanced or unbalanced.

  41. Force pairs What are the missing terms? Buoyancy Drag Thrust Weight

  42. Newton’s 1st Law of Motion • An object at rest will remain at rest unless acted on by an unbalanced force. An object in motion continues in motion with the same speed and in the same direction unless acted upon by an unbalanced force.

  43. Newton’s 2nd Law of Motion • Acceleration is produced when a force acts on a mass. The greater the mass (of the object being accelerated) the greater the amount of force needed (to accelerate the object).

  44. Newton’s 2nd Law of Motion • EX: Mike's car, which weighs 1,000 kg, is out of gas. Mike is trying to push the car to a gas station, and he makes the car accelerate at 0.05 m/s/s. Using Newton's Second Law, compute how much force Mike is applying to the car.

  45. Small constant force FORCE AND MOTION What happens when you apply a small constant force to a trolley and time it over a set distance? Set distance The trolley should accelerate because… An unbalanced force causes acceleration.

  46. Small constant force FORCE AND MOTION What happens when you apply a small constant force to a trolley carrying a 1kg mass and time it over a set distance? 1Kg Set distance The trolley should accelerate but slower than previously because… The larger the mass the slower the acceleration

  47. 150N 800N FORCES AND ACCELERATION Given the formula F = ma try the following questions. 1. What are the names and units of F, m and a? 2. Complete the table…. 3. The rider and cycle are 150kg: a. What is the Nett force? b. What is the cyclist’s acceleration? 4. A bike accelerates at 10ms-2 using a force of 6000N. The rider is 70kg. What is the mass of the bike?

  48. WEIGHT FORCE Weight is a force. It is therefore measured in… An object’s weight depends on two things… Newtons (N) • Gravity • varies depending where you are • 10ms-2 or 10N/Kg on Earth • Mass • does not vary • measured in Kg • A man with mass of 75Kg on earth weighs 750N • BUT on the moon he weighs 125N

  49. The Source of Friction • Friction- A force that opposes motion between 2 surfaces that are touching • Friction occurs because the surface of any object is rough. • The amount of friction depends upon many factors like: • Roughness of the surfaces • Force pushing the surfaces together

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