3. The Law of Conservation of Energy

3. The Law of Conservation of Energy

Concept Explanation:

The law of conservation of energy states that energy cannot be created or destroyed; it can only be transferred or converted from one form to another. This principle is a cornerstone of physics and applies universally across all processes, including thermodynamic systems.

In a closed system, the total energy remains constant, though it may change forms (e.g., from kinetic energy to potential energy, or from chemical energy to thermal energy). In thermodynamics, this concept is directly tied to the first law, which ensures that any change in a system's internal energy must be accounted for by the heat added to the system and the work done on it.

Example Problem:

A pendulum is released from a height where it has potential energy of 20 J. At the lowest point of its swing, what will be its kinetic energy, assuming no energy is lost to friction or air resistance?

Solution:

According to the conservation of energy, the potential energy at the highest point will convert entirely into kinetic energy at the lowest point, assuming no losses:

E_potential = E_kinetic

20 J = Kinetic Energy

So, the kinetic energy at the lowest point will be 20 J.