Question

Define kinetic energy.

Answer 1

Use the concept of energy of an object. Then recall the terms kinetic energy associated with the object. Give information about which type of objects possess kinetic energy. Give some examples of objects having kinetic energy. Also, give the mathematical expression for kinetic energy of an object.

Complete answer:
The energy of an object is the measure of the ability of an object to perform work.
The energy possessed by an object in motion is known as kinetic energy of that object.
Thus, every object in motion has kinetic energy.
For example, a running boy possesses kinetic energy. A moving insect also possesses kinetic energy.

Additional Information:
The mathematical expression for the kinetic energy of an object is given by
$K = \dfrac{1}{2}m{v^2}$
Here, $K$ is the kinetic energy of the object, $m$ is mass of the object and $v$ is velocity of the object.
From the above expression, we can conclude that the kinetic energy of an object depends on its mass and velocity.
The unit of kinetic energy from the above formula is ${\text{kg}} \cdot {{\text{m}}^{\text{2}}} \cdot {{\text{s}}^{{\text{ - 2}}}}$. But there is another most often used unit of kinetic energy joule (J) which is named after the physicist James Prescott Joule.
The CGS unit of kinetic energy is erg.
There are different types of kinetic energy such as sound energy, electrical energy, thermal energy, vibrational energy, radiant energy, mechanical energy, etc.

Note:
One should always define the linear kinetic energy and not rotational kinetic energy of an object when asked to define kinetic energy. The rotational kinetic energy is also the kinetic energy possessed by the object in rotational motion. But here the expected definition is that the kinetic energy of an object is linear or translational motion.