Kinetic energy may sound like a complicated term, but it’s actually quite simple. But before you can have kinetic energy explained, you must first understand energy as a concept.
Energy is the ability to do work — it’s when a force is applied to an object and it moves. Energy is also another form of mass, with relativity showing that mass and energy could be interchangeable by using the speed of light as a constant. This is shown in perhaps the most famous equation in history: E=mc2, where m is mass and c2 is the speed of light (or more precisely, the square of the speed of light).
Get ready to learn everything you need to know about kinetic energy and how it applies to your everyday life.
What Is Kinetic Energy and What Does It Mean?
Kinetic energy (KE) is the energy of a body in motion, which means it’s essentially the energy of all moving objects. It is one of the two main forms of energy, along with potential energy, which is the stored energy contained within objects at rest. Understanding kinetic energy is intuitively easier than understanding potential energy because it’s more obvious that moving things have energy.
The total kinetic energy of an object depends on several factors, such as the amount of work done on an object and its acceleration after a moment of inertia from external forces. The most important factors that determine kinetic energy are the motion (measured as velocity) and the mass of the object in question.
What Is Kinetic Energy the Energy Of?
Kinetic energy is really the converted potential energy found in all objects and dictated by forces of motion. In everyday life, two of the main catalysts of kinetic movement are gravitational potential energy and chemical energy.
Gravitational energy, as the name suggests, is the energy potential of objects that is released when Newtonian gravity pulls them towards the Earth. In chemical energy, the stored potential energy in molecular bonds is released as kinetic energy.
Kinetic energy is created when potential energy is released, triggered into motion by gravity or chemical reactions, among other catalysts. This results in a potential energy decrease and kinetic energy increase. The total kinetic and potential energy together is known as mechanical energy.
What Are the Characteristics of Kinetic Energy?
The main characteristics of kinetic energy are movement and moving objects. Kinetic energy is never present in an object at rest — only in objects that are moving. There are countless examples of kinetic energy at work in the real world: roller coaster rides, cars driving downhill, skydiving, hitting a golf ball, throwing a curling rock go on the ice, and any other time something is actively moving anywhere in the world.
What Is Kinetic Energy Measured In?
Kinetic energy is measured in the same units as all types of energy: Joules (J). A Joule is equal to the force of one Newton (N) acting along a length of one meter. This unit can be used to determine everyday energy usage in the form of electricity by a simple conversion:
1 kilowatt-hour (kWh), which is how electricity is measured in households, is equivalent to 3.6 million Joules.
For reference, most Americans pay about 12 cents per kWh of electricity, so it costs about $1 for about 30 million Joules of kinetic energy in an average household. However, this figure can vary depending on the electric company.
If you’re looking to find the kinetic energy of a non-electrical object, the equation for kinetic energy is KE = 1/2 m v2, where m is the mass and v2 is the square of its velocity.
What Are Some Kinetic Energy Examples?
There are countless examples of kinetic energy, both in free movement and in the form of electrical energy, which comes from the potential energy stored in electrons. Below are some more specific examples of kinetic energy in everyday life — and some examples of different forms of kinetic energy.
Examples of Kinetic Energy at Home
Anything at home that moves is an example of kinetic energy. This could be a cue ball rolling on a billiards table, a fan circulating air on a warm day, or glass shattering on the floor after it falls from the counter. Electrical devices that are turned on use kinetic energy as do people moving about the house. However, when devices are shut off, even while charging, they are full of potential energy, not kinetic.
Is Heat Kinetic Energy?
Also known as thermal energy, heat energy is kinetic in nature. Heat is created by molecular vibrations within objects, with faster vibrations equaling higher temperatures. These vibrations are kinetic energy at work since they are moving.
Are There Different Forms of Kinetic Energy?
Yes. While all movement is inherently kinetic energy, there are a few different forms that this movement can be classified under. Objects can be in motion due to rotation, translation, or vibration, which are the three main subcategories of kinetic energy. These subcategories comprise nearly all of the energy in motion throughout the known universe. Below we have these forms of kinetic energy explained.
Rotational Kinetic Energy
Rotational kinetic energy is created by moving objects around an axis. This type of energy depends on how fast the object is spinning, how much it weighs, and where the center of mass is located in relation to the axis.
Some examples where rotational kinetic energy is important include flywheels, molecules (for thermal kinetic energy), turbines, and the Earth, which rotates on its axis as well as around the sun.
Translational Kinetic Energy
Translational kinetic energy is caused by objects colliding with one another. The key component of this type of energy is that all molecules of an object travel in the same direction under the same force when it’s applied.
Translational kinetic energy depends on motion through space. A golf club striking a golf ball is a great example of this form of energy.
Vibrational Kinetic Energy
Vibrational kinetic energy is, unsurprisingly, caused by objects vibrating. It’s essentially the energy of an object due to its vibrational motion. A vibrating smartphone and the sound coming from a drum solo are two examples of vibrational kinetic energy.
What Factors Affect Kinetic Energy?
The two main factors that affect kinetic energy are mass and speed. Why? Because the motion of an object depends on how fast it’s traveling, but also how much mass it has, though velocity is the more important factor.
Since velocity is squared in the kinetic energy equation, increases in velocity have exponential effects: doubling the mass of an object will double its kinetic energy, but doubling the velocity of the object will quadruple this amount!
What Is Kinetic Energy in Chemistry?
Kinetic energy in chemistry is the same as it is in everyday life — there are just a lot more equations to determine the kinetic energy of an object as well as how to harness this energy and use it.
What Are Methods to Harness Kinetic Energy?
Kinetic energy can be harnessed in many imaginative ways. Since this form of energy is typically harnessed to be used as electrical energy to power our gadgets and devices, most of the methods to harness kinetic energy involve capturing movement to store as a form of renewable energy.
Some of the more common methods of harnessing kinetic energy include bike lights that use the power of pedalling to illuminate the bulb and turbines that use the power of wind or water to create hydroelectricity and wind power.
However, some more inventive methods have been popping up in recent years, including speed bumps that harness kinetic energy from moving cars, walking contraptions to power your handheld devices, and even kinetic dance floors that literally take the excess energy that is given off by partygoers.
While there is still much more research on the horizon, these examples show the creative ways in which kinetic energy is being harnessed and how it can develop into something that’s more usable in the future.
What’s the Problem With Trying to Harness Kinetic Energy?
It’s great to harness kinetic energy that would otherwise be wasted, but the main problem with this is that in a lot of instances storing kinetic energy is not reliable — and waste is almost always unavoidable. While harnessing the kinetic energy of rivers for hydropower or the blowing wind for wind power can provide significant amounts of energy, most other sources do not.
Kinetic energy must come from somewhere, so harnessing it is usually best in the form of electrical energy. This way, it can be stored for later use. However, the major issue is that massive amounts of this energy will be lost in the conversion to electricity, storage, and conversion back to usable energy. The reason for this loss of energy is due to the second law of thermodynamics.
What Is the Conservation of Kinetic Energy?
The conservation of energy, also known as Newton’s second law of thermodynamics, definitely applies to kinetic energy. The first law is that energy cannot be created or destroyed, it can only be transferred. The second law states that the quality of energy degrades over time — as energy is transferred or transformed, an increasing amount is wasted with each conversion.
SInce kinetic energy is converted to potential energy, and vice versa, and also harnessed, it is always conserved. However, it always loses energy along the process.
What Are The Main Rules for Kinetic Energy?
If there are any main points to take away from what kinetic energy is, it would be that it’s the energy of motion and it requires forces to act upon the objects to get them in motion.
It’s also important to take note of the three main subtypes of kinetic energy: rotational, translational, and vibrational. And don’t forget Newton’s second law, which states that the potential energy in any exchange will always be less than that of the initial state.
With those basics, you will be able to understand the main rules associated with kinetic energy — and have a better feel for the forces at work next time you drive downhill, ride a roller coaster, or hit a beautiful tee shot in a game of golf.
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