3 Mechanical systems 3.1 pose description and transformation
Unit d - section 3.1 -- evaluating a mechanical device
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Transcript of Unit d - section 3.1 -- evaluating a mechanical device
Evaluating a Mechanical Device
Mechanical devices have evolved over time due to advancements in science and technology
Look at the progression of the lawn mower
Was made of steel and moved by a person pushing it
The First Lawn mower
Moved onto using gasoline and electricity to make it much lighter and easier to use
Now we have moved onto more advanced forms such as ride on movers and even robotic mowers
In order for us to improve the machines we have today we constantly evaluate them
Companies use these evaluations to make their products better, different from other brands so people will buy them
Even you evaluate devices before you buy one
Evaluations
BlackBerry IPhone
WHICH WOULD YOU RATHER HAVE
In order for evaluations of a device to work there must be areas or criteria that we are looking at
These criteria are the areas of interest that we will be focusing on in order to decide which product to buy
Criteria to Evaluate a Device
Criteria;◦ What are we using our bike for?
Street riding? Trails Riding? BMX riding? Competition racing?
◦ Each of these features is part of your criteria for evaluating your new bike Each will lead you towards a different option…which
is right for you◦ Another important part to criteria is the COST
EX. BUYING A NEW BIKE
In previous notes we talked about how you can calculate efficiency by going MA/SR.
Efficiency can also be described in words by comparing how well or fast you can accomplish a task
A machine is efficient if it does its job well
Efficiency Vs Effectiveness
Effectiveness is related to how useful the machine is in the specific situation
The best machines combine high efficiency and high effectiveness
Using the lawn mowers as an example;◦ The push mower and the ride-in mower both are
effective at mowing the lawn but the ride in is far more efficient at it
◦ You cover the same distance but you do so quicker and by expelling less energy
Efficiency Vs Effectiveness cont….
Function is what the device is suppose to do
The design is the physical form of the device that makes it usable
Looking at racing bikes we can see how different designs affect how the function of it
Function and Design
Mountain Bike 21-speed Race Bike
Danny MacAskill – 5mins http://www.youtube.com/watch?v=iRN84UW
_tH0
Going Outside a Function
◦ You have just received your license and as deal with your parents they have agreed to give you $30,000 towards a car.
◦ However, they will not just buy you any new vehicle, they want to make sure you do your homework before you go off and decide on any vehicle
◦ Your job is to create a realistic criteria that you will be looking at before you even start shopping around for your perfect vehicle. You will be comparing 3 different models of vehicle and
comparing each of their criteria's to the one you made.
You will write a paragraph using your criteria on why the car you choose is the most appropriate
Evaluating a Device
You have $10,000 in your bank to put towards your car .
You will not be able to afford a new car with the money your parents give to you so you will have to make a choice;
1. Buy a car that totals $40,000 2. Buy a car that’s less then $40,000 and
keep the rest. You must buy a car worth at least $20,000