Can you lift the Empire State Building with the
weight of a notebook?
This weighs about a pound,
yet you can use the weight of it to lift
the empire state building.
How? Mechanical Advantage.  Mechanical Advantage is the amplification a force
using a mechanical device.
A simple machine amplifies the force I put
in giving me increased output force.
A lever is a simple machine
Archimedes once said "give me a long
enough lever and a place to stand and I
will move the Earth"
A lever can be balanced on a fulcrum
If we move the fulcrum to one side, it takes less weight on the long side
to lift the short side.
The Empire State Building is really big, 
let's look at a smaller example.
This car weighs considerably more than I
weigh but with the long enough lever
we can lift the car using only my body weight.  
Simple machines have been used for
thousands of years.  In fact they were
used to build the Pyramids and Stone Henge.
We still use simple machines to help us
to do work.  We find hinges gears, and four 
bar linkages in all sorts of products and 
we continue to build on the basic
principles.
Combining these objects to create
increasingly complicated machines that are
better at doing specific tasks.
Going back to the question of lifting
the Empire State Building
we'll have to estimate the weight of the
building.
it's a  187 feet wide so let's say its center select save center of gravity is 
100 feet from the fulcrum
To make it easy we won't factor in the
weight of the lever which would change
our calculation.  
We can do the math and see that our note book would have to be 
73 billion feet away from the fulcrum
That's nearly 14 million miles long
enough to wrap around the earth 
555 times
of course the lack of gravity in space
throws off the weight of our notebook,
but that's an issue for another video.  
Can we lift The Empire State Building
with the weight of a notebook?
it's impractical but theoretically, its possible.
