| Simple
Machines
Learn
about how these tools effect our lives.
Lever
A lever consists of three things, a fulcrum, a resistance
arm,
and an effort arm. The fulcrum is a fixed point on which the
lever pivots. The part of the lever where the effort is applied
is the effort arm. The resistance arm is the part of the lever
that exerts the resistance force. there three types of levers.
The first class lever is like a see-saw, with the fulcrum
in the middle and the two forces on either side. A nutcracker
is an example of a second class lever, the fulcrum being on
one side, the resistance in the middle, and the effort on
the other. A third class lever is a hockey stick, with the
effort in the middle, the fulcrum on one side and the resistance
on the other.
Inclined
Plane
Imagine that you are trying to get a box from the ground
to the second floor. But there are no elevators! What do you
do? A ramp is a sloping surface that is also known as an inclined
plane. Also, in using an inclined plane it allows you to do
less. What would be harder, lifting a box straight up or sliding
it? Just because sliding the box forces you to cover more
ground, it allows you to transport the box to higher levels
easier.
Pulley
The pulley system is used all around you. Flags are hoisted
up flagpoles by a system of pulleys and elevators. In essence,
a pulley is a lot like a first class lever, but instead of
a bar, there is a rope and instead of a fulcrum, there is
an axle. Now think about pulleys in amusement parks. They
are used in roller coasters! The pulley attaches to the bottom
of the train, pulls it up to the crest and then lets go and
sends the train plumeting down the hill. Whether it is movable
or fixed, they would both be pulleys. By pulling down on the
rope, you can raise an object, which means that this simple
machine has done its job, make your life easier.
Wheel
& Axle
Look around you and see if you can find an example of a wheel
and axle. Maybe a doorknob, a faucet handle or a clock? This
type of simple machine consists of two wheels of different
sizes that rotate together. Usually, the effort force is applied
to the larger wheel and the smaller wheel, or the axle exerts
the resistance force. In many cases the larger wheel dosen't
look like a typical circular wheel, but it always rotates
around the axle.
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