Moving parts in machines

Introduction:
Machines are devices that are designed to perform specific tasks or functions. They are composed of various components, including moving parts, which enable them to carry out their intended operations. In this context, the statement "________ contains moving parts" refers to the category of objects that possess components capable of motion. Among the options provided, the correct answer is option 'B', machines.

Explanation:
Machines:
- Machines are mechanical devices that use energy to perform work. They are typically composed of several components, including both stationary and moving parts.
- Moving parts in machines are crucial for their operation as they enable the conversion of energy into mechanical work.
- Examples of machines with moving parts include engines, conveyor belts, turbines, pumps, gears, and many more.

Frames:
- Frames, also known as structures, are rigid frameworks that provide support and stability to various objects.
- While frames can be a part of machines, they themselves do not contain moving parts. Their primary function is to provide structural integrity and resistance to external forces.

Truss:
- A truss is a structure composed of interconnected members designed to carry loads and resist forces.
- Similar to frames, trusses are primarily used for structural support and do not typically contain moving parts.

Beam:
- A beam is a structural element that is capable of withstanding loads and transferring them to supports.
- Beams are often used in construction and engineering projects to provide support and stability, but they do not possess moving parts.

Conclusion:
In summary, machines are the category of objects that contain moving parts. While frames, trusses, and beams are also important components in various structures and systems, they do not inherently have moving parts. Machines, on the other hand, are specifically designed to have moving components that enable them to carry out their intended functions.