Which two statements are true about a system? 1. A system is a group of objects analyzed as one unit. 2. Energy that moves across system boundaries is conserved. 3. There’s only one way to define the boundaries of a system. 4. All systems are made by humans.
The Correct Answer and Explanation is:
The correct statements are:
- A system is a group of objects analyzed as one unit.
- Energy that moves across system boundaries is conserved.
Explanation:
In the context of thermodynamics and system analysis, these two statements hold true:
- A system is a group of objects analyzed as one unit:
A system refers to a collection of objects or substances that are studied together as a single entity. This could be a gas, a chemical reaction, a mechanical system, or any other combination of matter that we focus on for analysis. The idea is to treat this collection as a unified “system” to simplify complex analyses. The system could be anything from a gas contained in a piston to an electrical circuit, depending on the context. - Energy that moves across system boundaries is conserved:
This statement reflects the principle of the conservation of energy, one of the fundamental laws of physics. The law states that energy cannot be created or destroyed, only transferred or converted from one form to another. When analyzing a system, energy can flow in or out of the system through work or heat transfer, but the total energy within the system and its surroundings remains constant. This is essential in thermodynamics, where the first law of thermodynamics emphasizes that energy conservation is central to understanding system behavior.
Why the other statements are incorrect:
- There’s only one way to define the boundaries of a system:
This is false. The boundaries of a system can be defined in many ways depending on the objectives of the analysis. For example, in thermodynamics, we could define the system’s boundary as the walls of a container, or we could use the surrounding environment as the boundary in a broader analysis. - All systems are made by humans:
This is also false. While humans may define or control systems in experiments or engineering, many systems exist naturally. For instance, the Earth’s atmosphere or the solar system are natural systems that operate without human intervention.
Thus, statements 1 and 2 are the true ones.
