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A thorough explanation of what is kinetic energy

Deriving its origin from the Greek word ‘kinesis’, meaning ‘motion’, kinetic energy is the energy that an object possesses due to its motion. This is a purely scalar quantity, i.e. it has no direction of its own and is measured in terms of Joules. Whenever a body moves with a certain velocity, it has an energy associated with it which is proportional to both the mass of the object and the square of its velocity. This energy is invaluable to our daily activities, most of which use kinetic energy either directly or in one of its various converted forms. From the daily morning shower to the electricity needed to run our lives, kinetic energy has a crucial role to play in some routine affairs of our lives.

The science behind it

Kinetic energy is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity. The body maintains this kinetic energy till its speed changes. The same amount of work is done by the body in decelerating from its current speed to a state of rest as in accelerating from rest to its current speed. Kinetic energy is interchangeable with potential energy, which is the energy that an object possesses due to its position. This is in accordance with the law of conservation of energy, which states that energy can neither be created, nor be destroyed but can only be converted from one form to another. Kinetic energy can also be transferred from one body to another through a collision. There is no loss in the total kinetic energy of the system as a whole if this collision is ‘elastic’. However, in real life, most collisions are ‘inelastic’, resulting in the loss of kinetic energy while it is being transferred from one object to the other. This loss can be due to various reasons such as the energy expended to overcome the inertia of the second object or due to friction with the surface or the surroundings in which the object is moving. These losses are harmful to our utility and hence need to be minimized in order to achieve maximum efficiency.

Kinetic energy and its inter-relations with other forms of energy are governed by certain equations. These include the classical Newtonian equations, Rotatory motion equations and the modern Relativistic equations. From these, it is fairly clear that the more mass an object has and the faster it moves, and the greater will be the energy associated with it. In fact, this kinetic energy remains with the body till there is a retarding force which negates it. It is this very principle that makes a ball thrown up into the air fall back to the ground whereas rockets which are beyond the effect of gravity revolve with their provided kinetic energy in space.

Sources of kinetic energy

Chemicals are the chief sources used to derive kinetic energy in today’s world. Certain chemicals, such as petroleum, upon combustion, convert their potential chemical energy into kinetic energy. Other sources of chemical energy include fossil fuels such as coal or certain explosives such as dynamite. It is also possible to derive kinetic energy from chemical energy by first converting it into heat energy through means such as nuclear fission and then using this heat energy to produce motion and hence kinetic energy.

Wind is one of the most commonly used natural sources of kinetic energy, along with water. Wind energy is harnessed in several ways such as through wind mills, by positioning the angled blades of a fan to catch the wind and connecting to a dynamo in order to produce electricity. Wind can also be harnessed by sailboats in order to propel them.

Water is a useful source of kinetic energy, especially when it is in motion. There can be turbines installed in such waters, fitted with fans having angled blades similar to those of the wind mills. However, stored water can also be used to generate kinetic energy by placing it at a height and then converting its potential energy to kinetic energy.

Human beings are great sources of kinetic energy themselves, with a great example being the motion of a bicycle through the energy applied by the driver on its pedals. There are also several instruments such as wind-up toys which require work done by humans in order to achieve motion.
Gravity is another natural source of kinetic energy, with objects having greater energy associated with them when they are dropped from greater heights. Since any object is constantly pulled towards itself by the earth, the moment it loses any support underneath it, it begins to accelerate towards the earth and hence gains kinetic energy.

Technology has made it possible for kinetic energy to renew itself through the Kinetic Energy Recovery Systems (KERS).These systems stop kinetic energy from being wasted during braking, store it in a reservoir and then reuse it to achieve better acceleration.
Uses of kinetic energy

When we think of kinetic energy, the first images that pop up in our minds are those of automobiles. In the case of automobiles, gasoline is converted from a liquid to a gas through the process of heating up and is injected into pistons, which in turn drive axles of the vehicle causing motion. We use this motion to travel to work daily, to reach our vacation spots and lots more.

An important use of kinetic energy is to drive trains, which are major connections across the globe, ferrying millions of people to and from their destinations. Trains were traditionally large consumers of fossil fuels, thereby depleting the resources as well as polluting the environment. However, with new technology in place, the consumption of fuel has been reduced and we now have trains which can be driven using much more efficient and clean energy.
Shock absorbers are used to store the energy obtained due to motion and then release them as necessary to music players, air conditioners, etc, in order to save fuel. Thus, kinetic energy not only helps in making automobiles more efficient and cheaper to maintain but also to conserve fuel, which is a valuable commodity that is quiclky running out.

A recent development uses a wheel chair’s own motion to power LEDs on its wheels. The kinetic energy provided by the movement of the chair is stored in the wheel itself, and the available amount of energy is shown on the small display in the center of the wheel. This helps oncoming vehicles to notice the wheelchair and thus allow safe passage.

Technology has always found ways of making the best of almost next to nothing. There are systems designed that use speed-bumps to garner kinetic energy and then re-use them in various applications. These are especially useful in today’s world, where the vehicular numbers are incredibly high and yet lots of energy gets wasted at simple obstacles such as speed bumps. The stored energy is then used to power the traffic lights, street lights, etc. thereby making the streets self-sustaining and reducing maintenance costs.

In certain places, dance floors have been fitted with special flooring, which helps to generate electricity from the impact of the feet on them. Thus, you can now help generate useful power while you have a good time. Similar technology as in the dance floors is employed in quite a few shopping centers and malls across the world to convert the footsteps of the countless visitors every day into energy, which is then internally consumed, helping to save on the use of natural resources and thus help the malls do their bit for the environment.

There have been instances of motors which have been powered by pedals, as have been lights. But the extent to which this technology has been improved comes to the fore when it is seen that pedals are now used to power laptops in certain regions of the world. This is an important and extremely useful technological marvel as it is a boon to areas which have an irregular power supply. Along with being inexpensive methods of generating power, these are also relatively simple technologies which can be widely adopted and are easy to use. Thus, kinetic energy helps people with little or no access to electricity enrich their lives with technology through inexpensive and feasible means.

While it might not necessarily be true that moving objects carry as much energy as is shown in quite a few movies today, it is certainly true that moving objects do have a kinetic energy associated with them and this energy, as it turns out, is quite useful. Not only is it clean & green, but is also easily convertible from one form to another and can be usefully applied in a variety of ways. Weigh in the fact that it can be derived from harmless sources such as the wind, water & gravity among others and it just might hold the key to the secure future of the world’s energy scenario.

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