Systems in Action Notes & Inquiry Questions

Simple Machines and Mechanisms Lever Wheel and Axle Pulley Wedge Inclined Plane Screw Read Section 5.1 from Text

Non-Mechanical Systems in Society Systems require organization This organization is usually done by a person, a company, or a government, who oversees the operation of the system. Once all of the procedures and components are put in place, the system can perform the desired task. Examples are transportation systems, education systems, hockey systems, health care systems, etc. Systems develop from a need To keep a system working efficiently, it needs to be monitored and managed frequently to make sure it is meeting the needs of its consumers.

Transportation system: An example Most cities in Ontario have a transportation system Mechanical components are busses, trains, or subways. Non-mechanical components are drivers, routes, and schedules By themselves, none of these components could provide an adequate transportation system

Inquiry Question: Types of systems Complete Question 6 in your inquiry question package

Inquiry Question: Systems to accomplish tasks Complete Question 1 in inquiry question package

Assessing the Impact of Automation and Alternative Systems Productivity Is the amount of output that is produced per unit of time. If you can increase productivity, you can accomplish a task faster or do more tasks in the same amount of time. Increasing productivity Often it is a combination of mechanical and non mechanical systems that increase productivity. Sometimes an increase in productivity means a decrease in jobs.

Assessing the Impact of Automation and Alternative Systems Mass production In the past, many consumer good were made by hand. For example, a small group of employees would build a car. Today, many consumer goods are produced by a system called mass production, in which an employee repeatedly performs a small task as the item moves past on a conveyer belt. This is an assembly line. This may reduce the quality of the product overall.

Assessing the Impact of Automation and Alternative Systems Automated systems An automated system replaces human workers with machines that are controlled by a computer. Once the automated system is set up, the machines monitor and react to situations without human intervention.

Inquiry Question: The Impact of Automation Consider all perspectives relating to the impact of automation, and answer Inquiry question #2

Inquiry Question: Mass production of furniture Consider all perspectives relating to the impact of automation, and answer Inquiry question #3

Efficiency The efficiency of a machine measures the useful work done by the machine compared to the work needed to operate it. Useful output work is the work that the machine is designed to perform.

Efficiency & Work done by friction When a machine is used to do work, parts of the machine are moving. When parts of a machine move, there is often friction. When using a pulley, work done by the force of friction transforms input energy into heat when the pulley wheel moves. Therefore, extra work must be done in order to compensate for the friction. This is why useful output work of a machine is always less than the input work.

Calculating efficiency To calculate efficiency, the useful output work (Wout) is divided by the input work Win). Example: A machine is capable of doing 35 J of work when 50 J of work is put into the machine. What is the efficiency of this machine? Efficiency = 𝑢𝑠𝑒𝑓𝑢𝑙 𝑜𝑢𝑡𝑝𝑢𝑡 𝑤𝑜𝑟𝑘 𝐽𝑜𝑢𝑙𝑒𝑠 𝑥 100% 𝑖𝑛𝑝𝑢𝑡 𝑤𝑜𝑟𝑘 𝐽𝑜𝑢𝑙𝑒𝑠 Efficiency = 35 𝐽 𝑥 100% 50 𝐽 Efficiency = 70%

Calculating efficiency: using forces and distances A 500N crate is moved up a 5m long ramp. What is the efficiency of this ramp if the person pushes with a force of 400N in order to raise the crate a vertical distance of 2.0m? Remember that W=fd Useful output work = (500N) (2.0m) = 1000 J Input work = (400N) (5.0m) = 2000 J Efficiency = 𝑢𝑠𝑒𝑓𝑢𝑙 𝑜𝑢𝑡𝑝𝑢𝑡 𝑤𝑜𝑟𝑘 𝐽𝑜𝑢𝑙𝑒𝑠 𝑥 100% 𝑖𝑛𝑝𝑢𝑡 𝑤𝑜𝑟𝑘 𝐽𝑜𝑢𝑙𝑒𝑠 Efficiency = 1000 𝐽 𝑥 100% 2000 𝐽 = 50% Complete Learning Checkpoint on p. 147

Assessing a System We use a variety of criteria to evaluate a system. To assess systems, the developers often use the following criteria: Efficiency Safety Cost Environmental impact Each criteria can be assessed quantitatively (numbers) or qualitatively (observations). Read examples of system assessments on page 169-170

Inquiry Question: Owners’ Manuals Answer question #5 in your inquiry question package relating to owners manuals and support services.

Inquiry Question: Environmental impacts Answer question #4 in your inquiry package relating to the impact on a change in the transit system on individuals, society and the environment.

Inquiry Question: System changes Answer question #8 in your inquiry question package