Some examples of kinetic energy from everyday life might be the motion of a roller coaster, a ball, or a car.
Kinetic energy is the energy that an object has when it is in motion and its speed is constant.
It is defined as the effort needed to accelerate a body with a given mass, making it go from a state of rest to a state with motion.
It is held that to the extent that the mass and velocity of an object are constant, so will its acceleration. In this way, if the velocity changes, so will the value corresponding to the kinetic energy.
When you want to stop the object that is in motion, it is necessary to apply a negative energy that counteracts the value of the kinetic energy that said object brings. The magnitude of this negative force must be equal to that of the kinetic energy for the object to stop (Nardo, 2008).
The coefficient of kinetic energy is usually abbreviated with the letters T, K or E (E or E + depending on the direction of the force). Similarly, the term “kinetics” is derived from the Greek word “κίνησις” or “kinēsis” which means movement. The term “kinetic energy” was first coined by William Thomson (Lord Kevin) in 1849.
The study of the movement of bodies in horizontal and vertical direction (falls and displacement) is derived from the study of kinetic energy. Penetration, speed and impact coefficients have also been analyzed.
Examples of kinetic energy
The kinetic energy together with the potential includes most of the energies listed by physics (nuclear, gravitational, elastic, electromagnetic, among others).
1 Spherical bodies
When two spherical bodies move at the same speed, but have different masses, the body of greater mass will develop a greater coefficient of kinetic energy. This is the case with two marbles of different size and weight.
The application of kinetic energy can also be observed when a ball is thrown so that it reaches the hands of a receiver.
The ball goes from a state of rest to a state of motion where it acquires a coefficient of kinetic energy, which is brought to zero once it is caught by the receiver.
2 Roller coaster
When the cars of a roller coaster are at the top, their coefficient of kinetic energy is equal to zero, since these cars are at rest.
Once they are attracted by the force of gravity, they begin to move at full speed during the descent. This implies that kinetic energy will gradually increase as speed increases.
When there are more passengers inside the roller coaster car, the coefficient of kinetic energy will be higher, as long as the speed does not decrease. This is because the wagon will have a greater mass. In the following image you can see how the potential energy occurs when climbing the mountain and the kinetic energy when descending it:
3 Baseball
When an object is at rest, its forces are balanced and the value of the kinetic energy is equal to zero. When a baseball pitcher holds the ball prior to pitching, the ball is at rest.
However, once the ball is thrown, it gains kinetic energy gradually and in a short period of time to be able to move from one place to another (from the pitcher’s point to the receiver’s hands).
4 Automobiles
A car that is at rest has an energy coefficient equal to zero. Once this vehicle accelerates, its coefficient of kinetic energy begins to increase, in such a way that, as there is more speed, there will be more kinetic energy.
5 Cycling
A cyclist who is at the starting point, without exerting any type of movement, has a coefficient of kinetic energy equivalent to zero. However, once you start pedaling, this energy increases. Thus, the higher the speed, the greater the kinetic energy.
Once the moment to brake has arrived, the cyclist must slow down and exert opposing forces to be able to decelerate the bicycle and return to an energy coefficient equal to zero.
6 Boxing and impact
An example of the force of impact that is derived from the coefficient of kinetic energy is evidenced during a boxing match. Both opponents can have the same mass, but one of them can be faster in the movements.
In this way, the coefficient of kinetic energy will be higher in the one that has a greater acceleration, guaranteeing a greater impact and power in the blow (Lucas, 2014).
7 Opening of doors in the Middle Ages
Like the boxer, the principle of kinetic energy was commonly used during the Middle Ages, when heavy battering rams were driven to open castle doors.
The faster the ram or log was propelled, the greater the impact provided.
8 Fall of a stone or detachment
Moving a stone up a mountain requires strength and dexterity, especially when the stone has a large mass.
However, the descent of the same stone down the slope will be fast thanks to the force exerted by gravity on your body. In this way, as the acceleration increases, the coefficient of kinetic energy will increase.
As long as the mass of the stone is greater and the acceleration is constant, the coefficient of kinetic energy will be proportionally greater.
9 Fall of a vase
When a vase falls from its place, it goes from being in a state of rest to movement. As gravity exerts its force, the vase begins to gain acceleration and gradually accumulates kinetic energy within its mass. This energy is released when the vase hits the ground and breaks.
10 Person on skateboard
When a person who rides a skateboard is in a state of rest, his energy coefficient will be equal to zero. Once it begins a movement, its coefficient of kinetic energy will gradually increase.
Similarly, if that person has a large mass or his skateboard is capable of going at a higher speed, his kinetic energy will be higher.
11 Rolling polished steel balls
If a hard ball is swung back and released to collide with the next ball, the one at the opposite end will move, if the same procedure is performed but two balls are taken and released, the other end will move. they will swing two balls too.
This phenomenon is known as a nearelastic collision, where the loss of kinetic energy produced by the moving spheres and their collision with each other is minimal.
12 Simple pendulum
A simple pendulum is understood as a particle of mass that is suspended from a fixed point with a thread of a certain length and negligible mass, which is initially in a balanced position, perpendicular to the earth.
When this particle of mass is displaced to a position other than the initial one, and is released, the pendulum begins to oscillate, transforming the potential energy into kinetic energy when it crosses the equilibrium position.
12 Elastic
By stretching a flexible material, it will store all the energy in the form of elastic mechanical energy.
If this material is cut at one end, all the stored energy will be transformed into kinetic energy that will pass to the material and then to the object that is at the other end, causing it to move.
13 waterfall
When water falls and cascades it is because of potential mechanical energy generated by height and kinetic energy due to its movement.
In the same way, any current of water such as rivers, seas or running water releases kinetic energy.
13 Sailboat
Wind or moving air generates kinetic energy, which is used to help propel sailboats.
If the amount of wind reaching the sail is greater, the sailboat will have more speed.
References

Academy, K. (2017). Retrieved from What is kinetic energy ?: khanacademy.org.

BBC, T. (2014). Science . Obtained from Energy on the move: bbc.co.uk.

Classroom, TP (2016). Obtained from Kinetic Energy: physicsclassroom.com.

FAQ, T. (March 11, 2016). Teach – Faq . Obtained from Examples of Kinetic Energy: techfaq.com.

Lucas, J. (June 12, 2014). Live Science . Retrieved from What Is Kinetic Energy ?: livescience.com.

Nardo, D. (2008). Kinetic Energy: The Energy of Motion. Minneapolis: Explorin Science.

(2017). softschools.com . Obtained from Kinetic Energy: softschools.com.