# Difference between Kinetic Energy and Potential Energy

• Last Updated : 30 Apr, 2022

The capacity to do work is called energy. This energy can be stored in various forms. Energy is one of the physical quantities because it is proportional to the mass of an object. The body’s ability to push or pull a natural force, such as gravity, determines what that energy is. Energy is ubiquitous and exists in many forms, the two most common of which is known as potential energy and kinetic energy. Although the way they interact with the physical world is very different, there are certain aspects that are complementary to each other. But to understand how they work, you must first understand what they are and what energy is. When an object is at rest, the body is said to have potential energy. In another case, when an object is moving, it is said to have kinetic energy.

Potential energy tends to affect only when objects in the environment are converted into other forms of energy. A rock at the top of a cliff is believed to be an example of a body with potential energy. When an object falls, it has kinetic energy. The energy stored in the body due to lifting is called the potential energy of gravity. Some objects, such as waterfalls, contain both kinetic and potential energy. The height of the waterfall is one of the basis of potential energy, and the movement of water is one of the basis of kinetic energy. A body’s properties determine the energy it contains. When an object moves potential energy is being converted into kinetic energy. Unlike potential energy, kinetic energy can be transferred from one object to another during a collision. ### Kinetic Energy

Energy is due to the movement of objects known as kinetic energy. Air pressure energy may cause potential energy to collect gravity or elasticity in other catalysts. Muscular energy is the energy of exercise. When the operation is performed in the facility, acceleration, the movement energy of the object increases. The most important factor that defines the kinetic energy is the mass of the object being considered and considering the movement (measurement at speed).

Although mass is a universal measure, the motion of an object can occur in a variety of ways, including rotation about an axis, oscillation, translation, or a combination of these and other motions.

Kinetic energy has three subcategories: vibration, rotation, and translation.
The kinetic energy of a vibration is naturally caused by the vibration of an object. When objects collide with each other by moving objects Rotational kinetic energy is produced.

Formula of Kinetic energy

K.E. = 1/2mv2

Where, m = mass (kg) and v = velocity (m/s).

### Potential Energy

In physics, potential energy is expressed as gravitational potential energy. Gravity is perhaps the most important element of physics because it is the foundation of the general theory of relativity, upon which all modern worlds are based. Potential energy is one of the important types of energy in the universe. It’s a bit difficult to understand intuitively, but it’s very simple. A form of energy that can potentially do work but does not actively exert a force on another object. The potential energy is found in the position of an object, not in the motion of an object. It is the energy of the location.

Formula of Gravitational potential energy

W = m × g × h = mgh

Where, m = mass (kg)

g = acceleration due to gravitational field (9.8 m/s2

h = height (m)

Elastic potential energy can be found using the formula,

U = 1/2kx2

Where k = spring force constant

x = stretch length (m)

Unit of energy = Joule (J).

Some Examples of Potential and Kinetic Energy.

The definition of potential and kinetic energy can be quite simple but it is not yet easy to say that any type of energy form in which energy forms energy are in a particular object or process.

• Planet: The motion of planets around the sun and other stars in the galaxy is the action of kinetic energy. Because they are attracted to large objects at the center of their respective orbits, they fall towards the center of mass due to their strong gravity. This gives rise to orbital motion and all motion is a form of kinetic energy.
• Rubber Band: A rubber band can be classified into potential energy and kinetic energy according to the state of the band. When the rubber band is stretched, it is filled with potential energy. When it is released, it gains kinetic energy. This is especially true if the rubber band carries other objects, such as stones thrown from slingshots.
• Rivers and Lakes: They are strictly working as kinetic energy. Water is in constant motion and every movement it constantly generates kinetic energy. The only case where rivers can have potential energy is when dams are built and energy is stored in artificial reservoirs to be used along with hydroelectric dams when needed.

### Sample Questions

Question 1: Are batteries kinetic or potential energy?

A battery is a form of chemical energy in which energy is stored in the bonds of molecules contained in the battery acid at its core. In other words, a battery is a form of potential energy into which all chemical energy is classified.

Question 2: Kinetic energy can be negative? Explain.

The general formula of kinetic energy is 1/2 mv2. According to this, as mass never be negative and here ‘v’ speed is the square and always give nonnegative term so kinetic energy cannot be negative.

Question 3: In a running competition, a boy whose weight is 20 Kg is running at a speed of 2m/s. Calculate the kinetic energy of the boy.

Solution:

Given: mass(m) = 20Kg

Velocity (v) = 2m/s

Kinetic Energy (K.E) = 1/2 mv2

K.E = 1/2 × 20 × (2)2

K.E = 40 Kgms-2.

Question 4: A box of mass 30 Kg is stored at a height of 10m. Calculate the potential energy of the box. Consider the value of acceleration due to gravity(g) = 10m/s2.

Solution:

Given: Mass(m) = 30Kg

Height(h) =10m and g = 10m/s2 .

Potential Energy = mgh

P.E = 30 × 10 × 10

P.E = 3000 Kgm2 s-2 .

Question 5: State whether sound energy is Kinetic or potential?

Sound is what most of us perceive as a kinetic form, but it can be considered as two forms of energy at the same time. The sound energy in the air produced by longitudinal waves that produce the movement of gas molecules is kinetic. Solids and liquids, which transmit sound farther than air, have both Kinetic and potential energy.

Question 6: Calculate the height of an object whose potential energy is 2000 Kgm2s-2 and mass is 20 Kg. Consider the value of acceleration due to gravity(g) = 10m/s2.

Solution:

Given: P.E = 2000 Km2s-2

Height(h) = 10 m  and g = 10 m/s

Potential Energy = mgh

2000 = 20 × 10 × h

h = 2000/20 × 10

h = 10 m.

Question 7: An object is moving with a velocity of 4m/s having a mass of 15 Kg. Calculate the kinetic energy of that object.

Solution:

Given: Mass (m) = 15 Kg

Velocity (v) = 4m/s.

Kinetic energy = 1/2 mv2

K.E = 1/2 × 15 × (4)2

K.E = 120 Kgm2s-2.

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