Machines employ power to achieve desired forces and movement (motion). A machine has a Franz Reuleaux wrote "a machine is a combination of resistant bodies so arranged that the mechanical forces of nature can be compelled to do work accompanied by Notice that forces and motion combine to define power.

Machine
A machine is defined as a combination of resistance bodies arranged to compel the mechanical forces of nature to do work accompanied by determinate motion. It is an essential component in the field of mechanical engineering and plays a crucial role in various industries and everyday life.

Definition of a Machine
A machine is a device that uses energy to perform a specific task by utilizing mechanical advantage. It consists of several components, including rigid bodies, links, joints, and mechanisms, all working together to transform input energy into useful output work.

Resistance Bodies
Resistance bodies are the components of a machine that provide the necessary resistance to the applied forces and allow the conversion of energy. These bodies may include levers, gears, pulleys, and other mechanical elements that interact with the input forces and transfer them to the desired output.

Compelling Mechanical Forces
The purpose of a machine is to compel or harness the mechanical forces of nature, such as gravity, electricity, or steam, to perform useful work. By manipulating these forces through the arrangement and configuration of the machine's components, the machine can achieve the desired output.

Determinate Motion
A key characteristic of a machine is that it produces determinate motion, meaning that the movement and operation of the machine are predictable and repeatable. This allows for the consistent performance of specific tasks and ensures the reliability and efficiency of the machine.

Example of a Machine
An example of a machine is a car engine. The car engine consists of various components, such as pistons, crankshafts, and valves, which work together to convert the chemical energy of fuel into mechanical energy. The resistance bodies within the engine, such as the pistons and crankshaft, compel the mechanical forces generated by the combustion process to produce rotational motion, ultimately propelling the vehicle.

Conclusion
In summary, a machine is a combination of resistance bodies arranged to compel the mechanical forces of nature to do work accompanied by determinate motion. It is a fundamental concept in mechanical engineering and is crucial in various applications where energy conversion and mechanical advantage are required. Machines play a vital role in society, enabling the automation and efficiency of numerous tasks.

The correct answer is machine (b)