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Kinetic Energy: Definition, Types, Formula And Examples

Kinetic energy is a form of energy that is produced when an object, substance, or particle is in motion. This energy depends mainly on the speed of the object, in addition to its mass. For example, when we run, our body is in motion, so it produces kinetic energy.

Kinetic energy definition examples and formula with picture

It helps explain the behavior of objects in motion and is crucial in various engineering applications.

Definition Of Kinetic Energy In Physics

Kinetic energy is the energy possessed by an object due to its motion. The amount of kinetic energy an object has depends on both its mass and its velocity.

Kinetic Energy (K.E) Formula

K.E. = 1/2 m v2

where:

  • is the kinetic energy,
  • is the mass of the object,
  • is its velocity.

Scalar Quantity:

Kinetic energy is a scalar quantity; it has magnitude but no direction. Unlike velocity, which is a vector, kinetic energy is simply a measure of how much energy is associated with an object’s motion.

Work and Kinetic Energy:

The work-energy principle states that the work done on an object is equal to the change in its kinetic energy.

K.E Units:

The SI unit of kinetic energy is the joule (J), which is equal to one kilogram meter squared per second squared.

Below we explain each term and the units used according to the International System:

  • Ec : is the kinetic energy measured in Joules or Joules , J.
  • m : is the mass of the body in motion, measured in kilograms, kg .
  • v : is the speed of the body, measured in meters per second, m/s . As this term is squared ( 2 ), the final units are 2 /s 2 .
  • The equation is divided by 2 , since the kinetic energy formula is the result of deriving and integrating Newton’s Second Law formula (Force = Mass · Acceleration) into the work formula (Work = Force · Displacement).

More Explanation of Kinetic ENERGY

Kinetic energy is linked to other physics concepts such as work and force. The object, being in motion, causes a specific work and force. For example, if the kinetic energy creates enough force, the object can deform or displace another.

An object in motion can return to its initial state or reach a state of rest if another force acts on it. The work caused by the external force counteracts that of the kinetic energy of the object. For example, a wheel that goes down a slope until it hits a wall. The wall applies a greater force on the wheel, so it will stop moving, reducing its kinetic energy to zero.

Likewise, an object generates kinetic and/or potential energy. When the object is at rest, the kinetic energy is zero, while the potential energy is maximum. If the object is in motion and there are no other forces acting on it, it generates kinetic energy, but not potential energy. Finally, an object moving within a gravitational field always generates kinetic and potential energy.

Different Types Of Kinetic Energy

There are three types of kinetic energy: translation, rotation and vibration.

Translational kinetic energy occurs when an object moves from one point to another. When moving in one direction, the acceleration applied to the mass of the object is translated into kinetic energy. Some examples are the action of walking, driving a vehicle on the highway, or falling objects.

Rotational kinetic energy occurs when an object rotates on itself. Although there is no displacement, part of the object accelerates around an axis, generating kinetic energy. Examples of this are the movement of records in players, the yo-yo, and the movement of windmill blades due to the wind.

The kinetic energy of vibration occurs when particles oscillate around an equilibrium point. Some examples are the vibration of the mobile phone, the movement of the strings of a guitar or molecular vibration.

In addition, kinetic energy can be represented in other types depending on the effect or type of energy they generate. These are:

  • Mechanical energy : the movement of objects and their physical interaction with others produces mechanical movement, the result of kinetic and potential energy. An example of this is when we hit a ball. The kinetic energy of our foot is transferred to the ball, producing mechanical energy in the form of displacement.
  • Thermal energy : the vibration and movement of the particles of a substance release heat, that is, thermal energy. Depending on the state of aggregation of the matter (solid, liquid or gas), the thermal energy will be greater or less.
  • Electrical energy : electrons, moving through an electrical circuit, generate electricity from their kinetic and potential energy.
  • Sound energy : It is a type of mechanical energy that results from the oscillation or vibration of particles in the form of waves. This oscillation generates sound waves that the ear can pick up.

Examples Of Kinetic Energy

  • A moving car has kinetic energy due to its velocity.
  • A thrown ball has kinetic energy while it’s in motion.
  • In sports, the kinetic energy of a moving soccer ball is important for understanding its impact.

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