Conservation of Energy

Definition

Conservation of energy is a fundamental principle in physics that states the total energy of an isolated system remains constant, it is said to be conserved over time. Energy can neither be created nor destroyed; rather, it can only be transformed or transferred from one form to another.

5 Must Know Facts For Your Next Test

1. The conservation of energy principle states that the total energy of an isolated system is constant; it is said to be conserved over time.
2. Energy can be transformed from one form to another, such as between kinetic energy and potential energy, but the total energy remains the same.
3. The work-energy theorem establishes the relationship between the work done on an object and the change in its kinetic energy.
4. Gravitational potential energy is the potential energy an object possesses due to its position in a gravitational field.
5. The conservation of energy principle is fundamental to understanding various physical phenomena, including the operation of simple machines, fluid dynamics, thermodynamics, and electromagnetic induction.

Review Questions

• Explain how the conservation of energy principle relates to the work-energy theorem and the concepts of kinetic and potential energy.
  • The conservation of energy principle states that the total energy of an isolated system remains constant over time. This means that energy can be transformed between different forms, such as kinetic energy and potential energy, but the total energy of the system will not change. The work-energy theorem establishes a direct relationship between the work done on an object and the change in its kinetic energy. As an object gains or loses kinetic energy, there is a corresponding change in its potential energy, but the total energy of the system remains the same, in accordance with the conservation of energy principle.
• Describe how the conservation of energy principle is applied in the context of simple machines and fluid dynamics.
  • In the case of simple machines, such as levers, pulleys, and inclined planes, the conservation of energy principle explains how these devices can be used to transfer or transform energy, allowing for the application of smaller forces to do work. The input work done on the machine is equal to the output work done by the machine, with any differences accounted for by losses due to friction or other dissipative forces. Similarly, in fluid dynamics, the conservation of energy principle is embodied in Bernoulli's equation, which describes the relationship between the pressure, velocity, and elevation of a fluid flowing through a pipe or channel. The principle of conservation of energy ensures that the total energy of the fluid, including its pressure, kinetic, and gravitational potential energy, remains constant along the flow.
• Analyze how the conservation of energy principle is fundamental to understanding the behavior of electromagnetic induction and the first law of thermodynamics.
  • The conservation of energy principle is crucial in understanding electromagnetic induction, as described by Faraday's law. This law states that a changing magnetic field induces an electromotive force (EMF) in a conductor, which in turn drives the flow of electric current. The conservation of energy ensures that the energy transferred from the changing magnetic field to the induced current is equal to the work done by the EMF. Similarly, the first law of thermodynamics is a restatement of the conservation of energy principle, stating that energy can be transformed from one form to another, but it cannot be created or destroyed. This law is fundamental to understanding the relationships between heat, work, and internal energy in thermodynamic systems, and it underpins the operation of various energy-converting devices, such as heat engines and refrigerators.

Related terms

Kinetic Energy: The energy of motion possessed by an object, equal to one-half the product of the object's mass and the square of its speed.

Potential Energy: The energy that an object possesses by virtue of its position or state, as opposed to its motion.

Work: The transfer of energy by a force acting through a distance.