How Physics Allows You To Lift Up Anything On The Earth
“Give me a place to stand,” contended Archimedes, “and I will move the world.”
Ignorant critics did not understand disdained Archimedes’ idea. They probably did not understand the working principles of the levers.
In this article, I will explain Archimedes’ quote by using examples from our daily life to demonstrate how levers amplify forces.
The lever rests on or is supported by a fulcrum. In the seesaw below, the fulcrum is where the board is attached to. The seesaw pivots around the fulcrum, which acts like a hinge.
The two children sitting on the seesaw act as loads. When the child with the red shirt applies a force with his feet on the ground, he applies an effort force, or effort. He consequently accelerates upwards. Simultaneously, a downward output force (the load) is applied to the child in the blue shirt.
In seesaws, both the effort and the load are equidistance from the fulcrum. Hence, how the input force is amplified is not readily observable.
Another example from our daily life is the shovel. The handle of the shovel is always longer than the part, that scrapes up target objects.
The force is magnified because it is applied over a longer distance and is exerted over a shorter distance.
Hence, Archimedes’ quote is proven true — If Archimedes constructs a lever that is extremely long, he can lift up the Earth.
Physics Proof
Let’s move on to the technical part.
Work can be modelled by the equation W = Fd. We can use the following equation to model the forces acting on a lever.
Energy is always conserved, so we can set the input energy to be equal to the output energy.
By manipulating algebraic variables:
To amplify the output force,
Hence, we have:
Thus, I can lift up the Sun if I have an infinitely long fireproof rod.
What do you want to lift up? Tell me in the comments!
