Final answer:
Physics deals with how machines and systems convert, transmit, and apply energy, with work being the transfer of energy through movement. Power is the rate of this energy transfer. Conservation laws and the relationship between mass and energy are also key concepts.
Step-by-step explanation:
The knowledge about using machines and systems to convert, transmit, and apply energy is a fundamental concept in physics, specifically in the study of mechanics and thermodynamics. When an external force is exerted on an object or system that causes it to move through a distance, the energy transferred in this process is known as work. In mechanical or electrical systems, energy transfer can happen at various rates. Power is then defined as the rate of energy transfer into, out of, or within a system. For instance, mechanical energy, which is the sum of kinetic and potential energy, is transferred in or out of a system during such interaction.
The conservation laws, such as those for energy, charge, linear momentum, and angular momentum, play a crucial role in these interactions. An important aspect of systems with internal structure is internal energy, which can change as the system's internal structure changes. The equation E = mc2 from the theory of special relativity, also indicates the interconversion between mass and energy under certain circumstances.