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Unit 4: Energy (Part 1) Page 10
Mathematically, work = force x plane, the wheel and axle, the
distance. lever, the pulley, the wedge, and
the screw. Every machine with
Work can be measured in Joules or moving parts, from a tape player
calories. to a car, from a computer to a
freight train is made up of simple
Power measures how quickly work machines. We are going to spend
can be done. time with two of the simple
machines. By learning how they
Mathematically, power is work work you will get a nice picture of
divided by time. all the simple machines and what
they do. In this lesson, we will be
Power can be measured in spending some quality time with
horsepower or Watts. levers and in the next lesson we
will spend time with pulleys.
Next lesson we will deepen our
study of energy by investigating The Power of Simple
the two main categories of energy,
potential and kinetic. Machines
Simple Machines Archimedes (286
to 212 B.C.) said
“Give me a place
This “making the force less” thing
is where simple machines come in. to stand and I
can move the
Way back when, folks needed to
move stuff. Long before there were Earth.” As you
can see,
cranes and bulldozers. They
needed to move heavy stuff, rocks, Archimedes was
quite fond of
boulders, logs, boats etc. These
simple
clever folks discovered machines.
A machine, in science language, machines. In fact, he was a master
of all the simple machines. He did
is any device that transmits or
modifies energy. In other words, not invent them but he did put
energy is put in to the machine and them to some amazing uses.
comes out of the machine but For example, a story goes that the
along the way the energy does
work, changes direction, changes Greek King Hiero had a problem.
He had had a boat made that was
form or all of the above.
so large no number of men could
get it into the water. What good is
We’re going to focus on the fact
a boat that is stuck on land? The
that machines can allow you to use
less force to do work. Most folks king told Archimedes his problem
and Archimedes said “Pfffft, I can
say that there are six simple
machines. These are the inclined launch that boat with one hand!”
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