Mechanical Systems 3 Flashcards
(14 cards)
what are the 2 criteria to evaluate a mechanical device?
● Features you want in your device
● Cost
Criteria need to be clear
explain the difference between efficiency and effectiveness (quantitative and qualitative)
Efficiency and Effectiveness
● We can quantitatively calculate how efficient a device is
● We can also look at is qualitatively
○ How quickly/easily does it help you complete the task at hand
● A machine works effectively if it does its job well
● You usually want the best combination of effective and efficient
what is the design?
Design: The physical form of the device that makes it useable
what is a function?
Function: what the device is supposed to do
what is a reason to evaluate devices?
to improve them
what does environment play a role in?
development
what is the key to pouring liquid out of a container?
● You need two holes or a large hole
● Two holes:
○ One hole allows the liquid out’
○ The other hole allows air to flow into the
can replacing the liquid
● One hole is big enough to allow the
liquid out and the air in at the same
time
what (was) a church key?
● First cans were completely sealed
● Church key was used to make
two holes in the top
● A lever with a pointed end that
multiples force and focuses it at
the point
why were removable tab tops created and how do they work?
● If you forgot your church key, you
couldn’t open your can
○ An improvement was needed
● Lever is included in the can
● Would open the can then snap off
● Problem of litter
explain cans with buttons?
● Two holes with buttons preformed in the
lid
○ One was smaller than the other
● Would press the smaller one first, as you
could exert a larger pressure over the
smaller area
● Press the large button once the pressure
in the can was released (easier)
● People didn’t like pressing two buttons,
the small one was often difficult
how did non-removable can tops work?
● Eliminated litter and is super
easy to use!
● It’s a lever just like the church
key
● Weaker lines outline the hole
○ You strain the metal along those
lines and pop the can open
how did advances in science result in new technology?
● Many devices we use today are only possible because
of electricity
● 1800s led to widespread distribution of electricity in
cities
● Were able to apply electricity to new technologies
explain MAGLEV trains
● Technology can develop from unrelated research
● MAGLEV trains are powered by electricity and float on
magnets
● Technology resulted from physics experiments using
particle accelerators
how did changes in the environment impact technology?
● People can observe the affect of
pollution and human impact on
Earth
● Sorting recycling
● Creating technologies that are
environmentally friendly
