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Nelson EducationSchoolPhysics 12 College Preparation | ||||||||||||||||||||||||||||||||||||||||||||||||||
Web LinksUNIT 3: HYDRAULIC AND PNEUMATIC SYSTEMSClick on a section below for related Web activities: Chapter 5: Fluid StaticsChapter 6: Fluid Dynamics6.1 Laminar and Turbulent Flow
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Floating Soap Ivory Soap floats because its density is less than the density of water. The floating was the result of an accident. In 1879, the operator of the soap-mixing machine went for lunch and inadvertently left the machine running. Extra air, stirred into the liquid soap, reduced its density on solidifying. However, customers liked the floating soap so much that it has been manufactured to float ever since. Read about the interesting history behind Ivory soap, and learn about how the manufacturer continues to produce soap that floats.
Ask a Scientist: Density and Floating Learn about density and why ice cubes and Ivory soap float in water. Also learn about the physical forces involved when solids float.
p. 223 Cargo Airships Large airships, shaped like a giant cigar, can rise in air because of the properties of helium gas. A new design, the SkyCat 200, is nearly 200 m long and can carry a load of up to 200 t, twice as much as a Boeing 747 jet. The airship moves forward at about 80 km/h. Helium, the low-density gas used in party balloons, is safe because it is not flammable.
Dynamics of Cargo Airships during the Load Exchange This page provides a brief description of the cargo airship, a picture of the structure, and how it is built.
This page provides information about the SkyCatT series, which combines airship technology with a lifting-body shape. The models described include SkyCatT 20, 200 and 1000.
Career Connection p. 226 Understanding how and when to apply pressure to muscles and tissue is important to registered massage therapists. RMTs must also learn about human anatomy and nutrition. Clients are varied, for example, people needing rehabilitation services after a car accident or sports injury.
Career Matters--Technical Occupations in Therapy and Assessment This site outlines the job description, required education, specific duties, and possible career opportunities for mechanical engineering technologists and technicians. It also provides a link that lists recommended high school courses students should take to prepare them for these careers.
Centennial College--Massage Therapy Program This page describes Centennial College's Massage Therapy program, including course descriptions, admission requirements, their student clinic area, and information about the massage therapy profession.
Ontario Massage Therapist Association This site describes the Ontario Massage Therapist Association, and allows you to do a search for massage therapists in your area.
Did You Know? p. 230 Comparing Plastic and Steel Some may think that a moulded plastic fuel tank must be lighter than a steel fuel tank. This is not necessarily so. A steel tank that is hydroformed can be very thin while maintaining its strength. In one comparison of tanks of the same fuel capacity, the mass of the steel tank was 7.2 kg and the mass of the plastic tank was 8.9 kg.
Hydroforming of Passenger Car Fuel Tanks This article reports the use of high-strength steel, stainless steel, and aluminum gas tanks. It also discusses manufacturing processes for fuel tank upper and lower shells and results from experiments.
Steel Industry Sets Sight on Auto Fuel Tanks This American Iron and Steel Institute article explains the advantages and disadvantages of replacing plastic fuel tanks with hydroformed steel.
Career Connection p. 231
Steel fabricators and sheet metal workers are integral to Ontario's manufacturing sector. These well-paid skills can be learned through apprenticeship programs.
This Ministry of Education site provides information on Apprenticeship trades and certification, modular training programs, and summary reports on apprenticeship. Apprenticeship in the Manufacturing Sector Learn about Apprenticeship training, opportunities, and the Ontario Youth Apprenticeship Program, as well as programs in auto service, construction service, and manufacturing sectors. This page lists general information about Mohawk College, the programs they offer, including Apprenticeship and technology and skills programs. Ontario Youth Apprenticeship Program This page describes the Ontario Youth Apprenticeship Program, and provides links to different opportunities available to students, including sheet metal worker.
p. 240
Units of Atmospheric Pressure Atmospheric pressure can be stated in terms of the height at which a liquid can be held in a tube such as the barometer invented by Torricelli. Thus, 76 cm of mercury is equivalent to about 101 kPa.
This page provides a brief history of Evangelista Torricelli and the barometer. It also explains how barometers work to measure air pressure and altitude.
This page describes the Toricelli barometer and how the height of mercury in the tube becomes a measure of the air pressure.
p. 244 Early Blood Pressure Experiment The first recorded experiment to measure blood pressure was made by Stephen Hales in Britain in 1733. He connected a 3.0-m vertical glass tube to a horse's artery using the trachea of a goose as a connecting tube. (A trachea is the tube made of tissue that carries air to the lungs.) After puncturing the artery with a sharpened goose quill, he observed that the blood rose 2.4 m above the horse's heart. This page provides information about the first blood pressure experiment in 1773, and how Hales introduced the concept of blood pressure. lood Pressure Measurements Millimeter of Mercury and Feel of Blood This article describes the evolution of blood pressure measurements from the time when the original experiment was performed to the time when blood pressure first became easy to measure. The units for blood pressure are also explained.
p. 245 Blood Pressure in a Giraffe Since the pressure of liquids increases with depth, why doesn't a giraffe faint when it raises its head or bleed when it lowers it? The giraffe has a complex system of valves and blood vessels in its brain, as well as a large heart, which enable it to control the differences in pressure. This course page describes the giraffe and how its long neck poses a challenge for the circulatory system. Find out how this unique mammal copes with the challenge. Learn about the giraffe's circulatory system and the characteristics of its heart that allow it to adapt.
p. 249 Shock Absorbers A car's shock absorber contains oil in an enclosed system. A piston with channels moves up and down in the absorber. As it moves, the oil squeezes through the channels, which slows down the piston's motion and results in a smoother ride.
This article explains what shock absorbers do and how they work. It also provides the scientific explanation of the geometry and mechanism of this device. This site provides information about the function of shock absorbers, how they work, and the different designs available.
Practice Questions p. 249 5. Many diesel trucks are equipped with compression release engine braking systems, also known as "Jake brakes." Research these brakes and describe their advantages. How does a Jake Brake Work on a Big Rig? Learn about Jake Brakes and how they work to provide braking power to vehicles. This site also provides links to relevant sites. Diesel Today: The Lowdown on Jake Brakes This article provides information about Jake Brakes and how they compare to other brake systems.
p. 251
8. Research the mechanics of today's power-assisted brakes and antilock brakes. (a) How do these features improve the performance of the braking system? (b) How do these features improve driver safety? This site explains how power, drum, and disc brakes work, as well as how antilock brakes perform.
Learn about the physics behind the brake system, and the mechanism of disc brakes, brake drums, wheel cylinders, and parking brakes. This site also provides a link to graphical and detailed information about the operation of antilock brakes.
p. 255 Actuators in Driver Simulators To simulate driving conditions, some advanced simulator vehicles use actuators connected to the axles instead of wheels. These hydraulic legs provide bumps and shakes, and even a realistic feel when turning.
The National Advanced Driving Simulator This University of Iowa site provides information about the National Advanced Driving Simulator, and employment opportunities for skilled technicians.
This site provides links to institutions that research driving simulators, training driving simulators around the world, and information on technological developments, teaching, and training.
Practice Questions p. 258 8. Some Web sites feature tutorials and self-quizzes on hydraulic and pneumatic systems. Find one that is at the appropriate level of difficulty, and try some of the questions posed. Describe features of the fluid systems and circuits shown on the site that are not discussed in this text. Plastic Professionals Resources This Plastics Professionals Resource site provides a tutorial on complete circuits, as well as a short quiz to test your knowledge. Industrial, Electrical, and Maintenance This site provides a tutorial on hydraulics, the symbols to repair a hydraulic or pneumatic machine, and a short quiz for practice.
Career Connection As more and more manufacturing becomes automated, there is a higher demand for automation and robotics technicians. In this career, you will use your knowledge of hydraulics, pneumatics, and electronics.
Humber College of Technology and Advanced Learning This Humber College site allows you to search for specific programs, such as automation and robotics technician diploma and certificate programs; and lists admission and registration requirements.
This page describes the college diploma or certificate programs offered by Centennial College. Career fields include aviation maintenance and automotive and robotics technicians.
p. 259 Early Robotic Manufacturing Automated machines have been used in the manufacturing industry for over 100 years, long before the computer age. For example, in 1908, Canadian inventor P.L. Robertson designed and manufactured the screw and screwdriver with the square hole that bears his name. A factory in Milton, Ontario, used robot-like machines to mass-produce the screws.
A Heritage of Quality and Innovation This site explains how the Robertson screw was invented, and provides information about the leading manufacturers of standard and specialty screws located in Canada, Mexico, and the United States.
Finding the Key: The Latest on Emerging and Evolving Technologies This article discusses the emerging technologies, and those that have been around for years but are now being improved. The discussion includes high-speed machining, automated machines, linear motors, and lasers.
p. 260 13. Robots are used in space and underwater exploration. Research Canada's involvement in one of these uses. Identify and analyze some of the social and economic consequences of the uses you researched. MD Robotics: World Leader in Space Robotics This site provides comprehensive information about space robotics, the Mobile Servicing System, and Satellite Servicing, and describes the information gathered from space that benefits us on Earth. This International Submarine Engineering Ltd. site provides information about Autonomous Underwater Vehicles (AUVs), as well as robotic manipulator systems for land, subsea, and space training applications. This International Submarine Engineering Ltd. page provides links to several Autonomous Underwater Vehicles sites, including the Underwater Research Lab in Vancouver, British Columbia. It also lists links to organizations, such as Canadian Standards Association, Canadian Technology Network, and National Research Council of Canada.
p. 275
28. Vacuum bagging is a method of attaching layers of components on a surface using the pressure of the atmosphere. By creating a partial vacuum on one side of a component, the atmosphere exerts a pressure on the other side. This process is especially useful in applying layers on curved surfaces, such as on surfboards, snowboards, and sailboards, where clamps would not work well. Research vacuum bagging in magazines or on the Internet. (a) In a sketch, illustrate the layers of materials in a vacuum bagging process. (b) What is a typical pressure used in the process? What devices can be used to achieve such a pressure? (c) Describe difficulties in the process that you would have to overcome in vacuum bagging your own sailboard or other device. (d) Describe what else you discovered in your research.
This site explains the process of vacuum bagging of fiberglass and resin parts. It lists the equipment and supplies necessary to create a vacuum. This page describes the technique of vacuum bagging, as well as its advantages and limitations. This journal describes a boarder's attempt to make a sailboard using vacuum bagging techniques.
CHAPTER 6: FLUID DYANMICS
p. 279
Practical nurses have a background in physiology, anatomy, and computer applications. Employment opportunities exist in a variety of areas, for example, hospitals, retirement homes, doctors' offices, and in industry.
This page lists general information about Mohawk College, the programs they offer, including employment opportunities for practical nurses.
Seneca College--Practical Nursing This site provides admission requirements, program description, provincial registration, course list, and contact information for the practical nursing program at Seneca College.
Practice Questions p. 281 7. Shelters for livestock are built to control snowdrifts. Research the design of these shelters. (a) Draw a diagram of the shelter design. On your diagram, show the predominant wind direction and the snowdrift patterns likely to develop. (b) What must the livestock owner be aware of when using this type of shelter? Wind Protection to Shelter Livestock This page explains how semicircular and wedge-shaped shelters build snowdrifts and protect shelter zones from wind.
This Agriculture and Agri-Food Canada site explains how to plan shelterbelts, suggests designs, and provides recommendations for spacing and weed control.
p. 282
Try a computer simulation to help visualize drag.
This Interactive Physics site provides an easy-to-use program which enhances physics instruction by modelling and simulating a variety of physical phenomena.
Did You Know? p. 283 Unique Wind Tunnels Imagine an enclosed tunnel built for cyclists who simply sit on their bikes and let the wind in the tunnel carry them along for several kilometres. This type of tunnel is proposed for linking cities in Holland, a country where 80% of the population own bikes. Fans above the tunnel would provide a tailwind for the cyclists. Of course, two tunnels would be needed to allow two-way traffic. If you were on a bike in such a tunnel, what posture would give you maximum speed?
Dutch Harness the Wind for a Bike-friendly Highway Read about Trans Glide 2000 Bicycle Transit System's proposed bicycle highway. Learn how it will change travel in Holland and the environmental implications of this new transportation system. NASA's Observatorium Wind Tunnel This page provides an article describing the wind tunnel, and the Math, Physics, and Space Science concepts that govern its operation. It also includes a quiz about wind tunnels and links to relevant Web sites.
p. 284
Designing Better Golf Balls At one time, golf balls were smooth. Then it was discovered that a ball with scratches travels farther than a smooth ball. Now, the surfaces of golf balls are dimpled. Experiments verify that a golfer can drive a dimpled ball up to 25% farther than a smooth ball of equal mass! As a smooth ball travels through the air, laminar flow produces a high pressure at the front of the ball and a low pressure at the rear, creating a large drag. As a dimpled ball travels through the air, however, there is just enough turbulence to cause the pressure difference between front and rear to be minimal, thereby reducing drag.
This site describes the physics behind golf balls, how their shape, size, and other factors affect how they perform, and how to give golf balls additional flight and/or spin. This article explains how golf balls fly, the discovery of the dimple, and the laws of physics that govern how far and fast golf balls can be driven.
Career Connection
p. 284
Sailboard designer entrepreneurs not only understand the principles of streamlining, but must also be familiar with material textures as well as construction and laminating procedures.
This site provides information about windsurfing and kite boards, and up-to-date news about kiteboarding and formula racing.
This page describes the cutting edge technology shaping machine for designing surfboards, sailboards, kiteboards, and paddleboards.
Practice Questions
p. 286
10. Using the Internet or another resource, research drag for Formula 1 racing cars. (a) How is the drag coefficient calculated? (b) Why do the drag coefficients of these cars tend to be so much higher than the coefficients of passenger cars?
This page describes drag and downforce, the aerodynamic forces that determine the top speed that a car can attain. It also shows how the aerodynamic coefficient can be calculated.
This page describes the role of aerodynamics in racing cars and the technological trends behind the success of racing cars. The page also includes related links to information about high-lift systems, aerodynamic drag, and calculation of drag coefficients.
The Physics of Flight There is more to airplane flight than lift, as explained by Newton's third law of motion and Bernoulli's principle. Control components such as flaps are also needed. These components are examples of hydraulic systems; they aid in takeoff, landing, changing altitude, and steering the plane.
This term paper describes the physics of flight, and the four forces of lift, weight, thrust, and drag.
This site describes various topics related to flight physics, including computational fluid dynamics, unsteady aerodynamics, airflow control, high lift devices, and computational acoustics. Airplane Flight Dynamics: Open & Closed Loop This page describes the aerospace courses offered by the University of Kansas, and the daily curriculum.
Learning Tip
p. 293 Curveball Simulation You can pitch a curveball online and see the airflow around the baseball. You can choose from a few locations, including Mars!
This NASA CurveBall program allows you to throw a ball by changing the values of the factors that affect the aerodynamic forces on the ball.
Questions
p. 296 6. Windsurfing boards are designed for maximum speed and stability in a variety of wind conditions. However, the problems created by high winds are different from problems created by low winds. Research windsurfing boards, and find out how the vented nose on the board reduces the tendency of the board to lift off and "tail walk" in high winds.
This site provides information about windsurfing and kite boards, and up-to-date news about kiteboarding and formula racing.
This American Windsurfing Industries Association Web site describes windsurfing, the new advances in the equipment, taking windsurfing lessons, and how to become a certified surfer.
p. 303 Option 3 Independent Study Your task is to propose an independent study task involving at least one important application of topics in Unit 3. Your proposal should include the following:
Product assessment Have your teacher approve your choice before you begin the research.
This site provides information about windsurfing and kite boards, and up-to-date news about kiteboarding and formula racing.
This page provides information about the SkyCatT series which combines airship technology with a lifting-body shape. The models described include SkyCatT 20, 200 and 1000. Hydroforming of Passenger Car Fuel Tanks This article reports the use of high-strength steel, stainless steel, and aluminum gas tanks. It also discusses manufacturing processes for fuel tank upper and lower shells and results from experiments. Learn about the physics behind the brake system, and the mechanism of disc brakes, brake drums, wheel cylinders and parking brakes. This site also provides a link to graphical and detailed information about the operation of antilock brakes.
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