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Law of Conservation of Energy, Definition of the Law of Conservation of Energy
Law of Conservation of Energy
- The law states that energy can neither be created nor destroyed - only converted from one form of energy to another.
- It means that a system always has the same amount of energy, unless itีs added from the outside.
- This is particularly confusing in the case of non-conservative forces, where energy is converted from mechanical energy into thermal energy, but the overall energy does remain the same.
- The only way to use energy is to transform energy from one form to another.
Details
- Conservation of energy, principle of physics according to which the energy of interacting bodies or particles in a closed system remains constant.
- The first kind of energy to be recognized was kinetic energy, or energy of motion.
- In certain particle collisions, called elastic, the sum of the kinetic energy of the particles before collision is equal to the sum of the kinetic energy of the particles after collision.
- The notion of energy was progressively widened to include other forms
- Energy is required for the evolution of life forms on earth. In Physics, it is defined as the capacity to do work.
- Energy exists in different forms in nature. You have learned about various forms of energy โ heat, electrical, chemical, nuclear etc.
- This law is known as the law of conservation of energy.
Definition of the Law of Conservation of Energy
- The law of conservation of energy states that
Energy can neither be created nor be destroyed, it can be transformed from one form to another
- By taking all forms of energy into account, the total energy of an isolated system always remains constant.
- All the forms of energy follow the law of conservation of energy. In brief, the law of conservation of energy states that
- In a closed system, i.e.. , a system that is isolated from its surroundings, the total energy of the system is conserved.
- This law means that a system always has the same amount of energy, unless itีs added from the outside.
- This is confusing in the case of non-conservative forces, where energy is converted from mechanical energy into thermal energy, but the overall energy does remain the same.
Energy Transformation
- To use energy is to transform energy from one form to another, the only way.
- The amount of energy in any system is determined by the following equation:
- = the total internal energy of a system.
- = the initial internal energy of a system.
- W = the work done by or on the system.
- Q = the heat added to, or removed from, the system.
To determine the change in internal energy of the system using the equation:
- This is a statement of the first law of thermodynamics.
- In the 20th century, Einstein figured out that even mass is a form of energy.
- The amount of mass directly relates to the amount of energy, as determined by the most famous formula in physics:
- E = the amount of energy in an object or system.
- m = the mass of the object or system.
- C = the speed of light, roughly