Zusammenfassung der Ressource
Machines
- What does machine do?
- change the size
- make things speed up
- change the direction of a force
- Mechanical advantage
- load
- Is the force actually required to do a job.
- force multipliers
- machine that increases the force
applied for a task.
- speed multipliers
- requires a small movement of
an effort to produce a large
movement of a load
- Lever
- first-class lever
- the fulcrum is positioned between the
effort and load
- pliers, tin snips, hedge-cutters, scissors.
- second-class lever
- when the load is positioned
between the fulcrum and the
effort
- a wheelbarrow, bottle
openers, paper
guillotines, and
nutcrackers.
- third-class lever
- when the effort is
positioned between the
fulcrum and load.
- tweezers, tennis racquets, cricket bats.
- A lever is a simple machine that is made of
a long rigid object (like a stick or metal rod)
- Increase the size of the effort
that you can apply or reduce
the effort needed, making the
job easier
- using a hammer as a lever reduces the size of
the effort needed to pull a nail from a piece of
wood.
- pivot or fulcrum
- Point about which lever rotates at
- How do you get a job done ?
- You apply a force known as effort.
- Wheels
- rim
- outer edge of a wheel
- axle
- a rod or spindle (either fixed or rotating) passing
through the centre of a wheel or group of wheels.
- results in a large force
- apply a slow force
- increases speed
- a fan
- Pulleys
- change direction of a force
- reduces effort force when multiple
pulleys are used
- Gears
- a wheel with teeth as rims
- change direction of a force
- increasing speed
- bicycle gears, clock, hand drill
- Inclined plane
- a sloping ramp up which heavy loads can be
raised by ropes or chains.
- zip
- a device consisting of two flexible strips of metal or plastic
with interlocking projections closed or opened by pulling a
slide along them, used to fasten garments, bags, and
other items.
- wedge
- a piece of wood, metal, etc. having one thick end and
tapering to a thin edge, that is driven between two
objects or parts of an object to secure or separate them.