Energy, Physics


The term energy may be defined as the capacity for doing work.  There are two forms of energy: potential energy and kinetic energy.


Potential energy is the stored energy possessed by a system, because of the relative positions of the components of that system.  If work done raises an object to a certain height, energy will be stored in that object in the form of the gravitational force.  This energy, waiting to be released is called potential energy.  The amount of potential energy a system possesses is equal to the work done on the system previously.

Potential energy can be found in forms other than weights and height.  Electrically charged components contain potential (electrical) energy because of their position within an electric field.  An explosive substance has chemical potential energy that is released in the form of light, heat and kinetic energy, when detonated.

Example :

A weight of 50 pounds is raised 5 feet. Using the formula:

Potential Energy = Force x Distance

= 50 x 5

= 250 ft-lb's.

Note: That energy is expressed in the same units as those used for work and in all cases energy is the product of force x distance.


Kinetic energy is the energy possessed by an object, resulting from the motion of that object.  The magnitude of that energy depends on both the mass and speed of the object.  This is demonstrated by the simple equation:

Energy =½mv2     or w v2


where m = mass, v = velocity (in feet or metres per second), w = weight, g = gravity (32 ft/sec2 or 9.81m/sec2).

All forms of energy convert into other forms by appropriate processes.  In this process of transformation, either form of energy can be lost or gained but the total energy must remain the same.


A weight of 50lbs dropped from a height of 5 ft has kinetic energy of

KE = 50 x 25

         2 x 32

     = 19.53 ft-lb's


Posted Date: 9/11/2012 6:28:44 AM | Location : United States

Related Discussions:- Energy, Assignment Help, Ask Question on Energy, Get Answer, Expert's Help, Energy Discussions

Write discussion on Energy
Your posts are moderated
Related Questions
What is the raw file size for an image of 80 rows and 100 columns, with pixels on 14 bits and with an extra row for the header? The minimum and maximum values observed in a

Q. Give any two differences among Peltier effect and Joule's law of heating. Joule's law of heating Peltier effect Takes place all th

a. Describe the radiation resistance of an antenna. b. With sketch, explain the feed mechanism of a parabolic reflector c. Explain the given term:- (i) Horn Antenna (ii

Explain the Nuclear Notation? Chemical reactions deal with the number of electrons exchanged or shared.  Nuclear reactions, on the other hand, involve protons and neutrons and

Define the characteristics of Heterojunction laser. Heterojunction laser: The threshold current density for homojunction lasers is extremely large because of poor optical an

Differentiate between Fraunhofer's and Fresnel's type of diffraction?

How does laser printer works? When a text or image is entered into the CPU, it makes a series of varying voltages. This controls a LED (light emitting diode) in the printer. Th

Question: Which one of the subsequent is true of electric potential but isn't true of an electric field? Answer: The electric field acquaintances a vector with empt

Applications of Superconductors - 1. Electrical Machines  2. Power Cables 3. Electro Magnets  4. Amplifiers 5. Cryotron 6. Magnetic Leviation 7. A 15 Phases

Q. Illustrate why is there more friction when you push an object than when you pull it? Answer:- Friction doesn't differ depending upon whether an object is pushed or pull