The universe, as we can see it, is presently full of uncountable phenomenon that will not be fully be discovered, investigated, and understood in our lifetime. Most likely, the human race with vanish from this universe before we can unlock every mystery the cosmos can offer us. However, we stand a chance of understanding our own world and the forces that govern it. If you’re going to start somewhere, start with your home.
As we’ve evolved and developed as a human species, especially when it comes to scientific advancement, understanding energy has been the crux of our focus. Granted, the areas of materialistic concern are the most popular, including energy sources like solar, fossil, nuclear, and so on. However, all of these energy sources are all examples of a greater energy.
I’m talking, of course, about kinetic energy. Kinetic energy is the energy given to an object in motion. It’s among the more easily and widely understood forms of energy that exists in the universe. Kinetic energy can be seen in light, heat transfer, running, speaking, and lightning - to name a few examples. The object doesn’t necessarily have to have mass to possess kinetic energy either, like gamma or x-rays.
Kinetic energy is a universal constant, but when it comes to examining an object’s total kinetic energy, the standard equations used to calculate that may not be sufficient. For instance, when calculating the total kinetic energy of the Earth, its rotation is considered. From here, we have to understand something known as rotational energy.
What Is Rotational Energy?
Let’s give a scale comparison of what rotational energy is first. The Earth spinning on its axis is a good example but, on a smaller scale, you can use any globe. If you take the globe and give it a good spin, that kinetic energy generated by its rotation is what is known as rotational energy. Rotational energy is also known as angular kinetic energy, but rotational energy is easier to remember.
It’s important to note that rotational energy is not some entirely separate, new form of energy in the universe. Energy only
falls into two categories: potential and kinetic energy. Rotational energy is simply another type of kinetic energy, usually seen in how it is generated and expressed.
The basic principle behind generating rotational energy is rotating any mass-filled object around a center of rotation. For the Earth, that center of rotation would be the core, which our planet rotates around as a pivot point. The faster the object rotates; the more energy is created.
Unlike with traditional calculations used to uncover the kinetic energy an object produces; rotational energy uses different equations. Kinetic energy is essentially defined by how the mass and speed an object is going. The faster and heavier an object is traveling, the more energy is produced.
For rotational energy, more factors are involved since the object in question produces different numbers due to its rotation. It’s not just the speed and mass - the rotation itself generates its own force. Put simply, to find the rotational energy of an object, you’ll need to know its angular velocity and moment of inertia.
Angular velocity is the quantification of an object’s angle and its speed. See, velocity isn’t just speed, it’s how far something goes in a specific time period. Since, with a rotating object, the direction is always changing, the velocity is different from the speed at which it moves. Finding the angular velocity means to find how much distance is covered in a revolution over a specific period of time.
For example, if you stuck a pencil in America on a globe and spun it, how much of the circumference of the globe that pencil will travel is dependent on how fast it goes. Combing how fast the globe spun with the distance traveled is the boiled down version of what its angular velocity is.
To understand the moment of inertia, you need to understand inertia. Inertia is how much resistance an object puts up with a change in motion. The faster you’re driving a car, the harder it is to make a sharp turn. The more mass and speed an object has, the more inertia it will possess.
Describing the moment of inertia, otherwise known as an object’s angular mass, is a bit easier than describing its angular velocity. Basically, all that comprises the moment of inertia is an object’s mass multiplied by the square of its radius. However, that specific equation only applies to a two-dimensional object. Third-dimensional physics gets a little more complicated.
Simply put, the moment of inertia is an object’s resistance to angular change in motion.
To bring it all together, finding an object’s rotational energy requires knowing its angular velocity and moment of inertia.
What Can Rotational Energy Be Used For?
Well, I’m glad you asked! Due to its ability to create energy through rotation rather than forward movement, creating rotational energy is a great way to produce other forms of energy. The rotational energy generated from any number of engines or generators can easily be turned into various other forms of energy: electrical, sound, heat, or translational energy.
As mentioned already, rotational energy is utilized beyond just keeping our Earth spinning. Properly harnessed, it can provide the energy requirements to keep large-scale vehicles running. For instance: the flywheel is a mechanism found in various mechanical forms designed specifically to store rotational energy for use.
The flywheel has been used for centuries to provide the needed continuous energy output needed for mechanisms to continue running. It can be found in something as simple as a potter’s wheel and as complicated as a NASA module. They’re fantastic for ensuring conservation of the energy used on large engines, such as your car. The more you start and stop, the more momentum and energy your waste.
Flywheels are designed to maintain their inertia as efficiently. They’re pretty hefty pieces of machinery, so they take some effort to get moving. However, due to physics and whatnot, that also means it takes some effort to make them stop. Since they maintain their momentum and inertia so effectively, they conserve that rotational energy.
In cars, this effectiveness is what takes that energy that you waste while braking and uses it later. For something simpler and much older, the flywheel is what makes the potter’s wheel go round. Modern potter’s wheels have motors that produce the spinning, but historically they were human-powered. Before the advent of motor technology, these flywheels were hand-operated for the most part through a variety of means.
Regardless of how the potter’s wheels achieved their momentum, they relied on the same concepts that flywheels have always used. The rotational energy generated through the fast-spinning, inertia-heavy potter’s wheel functions in the same fashion as it does in the modern automobile. The conservation of rotational energy creates an efficient, smooth operation ensuring effective car performance and quality pottery.
The flywheel is responsible for harnessing the power of rotational energy and has found applications in numerous fields from ancient to modern eras. We’ve already mentioned its use in pottery wheels, NASA modules, and cars, but its usefulness stretches even beyond those. Modern factory machines, trains, engines of every size and make rely on rotational energy to create highly-optimized performance.
A Conclusion Adhering to Rotational Force's Presence In Nature
Jump up and down a little. Run around outside and enjoy the sun. If you have one, you might want to spend a night stargazing through a telescope and catching a planet in the sky. Without the presence of rotational energy in the universe, we would not have a planet beneath our feet. The Earth would not be rotating, there’d be no life sustained, and we wouldn’t be here.
It’s not like we have to thank an intangible physics constant for all life. You don’t need to thank gravity for keeping your feet on the ground, or chemical reactions for allowing you to breathe. Sometimes, it’s good to simply learn about what makes the world tick. It’s all in the pursuit of higher knowledge.