General
Energy is a scalar quantity and the mechanical energy of a system is the sum of the potential energy which is measured by the position of the parts of the system, and the kinetic energy which is also called the energy of motion:
The potential energy, U, depends on the position of an object subjected to a conservative force. It is defined as the object's ability to do work and is increased as the object is moved in the opposite direction of the direction of the force. If F represents the conservative force and x the position, the potential energy of the force between the two positions x1 and x2 is defined as the negative integral of F from x1 to x2:
The kinetic energy, K, depends on the speed of an object and is the ability of a moving object to do work on other objects when it collides with them. It is defined as one half the product of the object's mass with the square of its speed, and the total kinetic energy of a system of objects is the sum of the kinetic energies of the respective objects:
The law of conservation of mechanical energy states that if a body or system is subjected only to conservative forces, the total mechanical energy of that body or system remains constant. The difference between a conservative and a non-conservative force is that when a conservative force moves an object from one point to another, the work done by the conservative force is independent of the path. On the contrary, when a non-conservative force acts upon an object, the work done by the non-conservative force is dependent of the path.
Read more about this topic: Mechanical Energy
Famous quotes containing the word general:
“We have grown literally afraid to be poor. We despise anyone who elects to be poor in order to simplify and save his inner life. If he does not join the general scramble and pant with the money-making street, we deem him spiritless and lacking in ambition.”
—William James (1842–1910)
“The general interest of the masses might take the place of the insight of genius if it were allowed freedom of action.”
—Denis Diderot (1713–1784)
“I suggested to them also the great desirability of a general knowledge on the Island of the English language. They are under an English speaking government and are a part of the territory of an English speaking nation.... While I appreciated the desirability of maintaining their grasp on the Spanish language, the beauty of that language and the richness of its literature, that as a practical matter for them it was quite necessary to have a good comprehension of English.”
—Calvin Coolidge (1872–1933)