What pneumatic component provides straight line motion?

The component that provides straight line motion in pneumatic systems is the cylinder. Pneumatic cylinders, also known as actuators, are devices that convert compressed air energy into linear mechanical motion. They consist of a hollow cylinder with a piston that moves back and forth within it when air is applied to one side of the piston. This action results in a straight line motion that can be utilized for various applications such as moving machinery parts, pushing or pulling loads, and operating automated processes.

Other components mentioned, like motors, direction control valves (DCV), and mufflers, serve different purposes. Motors typically provide rotational motion rather than linear motion. Direction control valves manage the flow of air to the cylinders but do not themselves produce motion. Mufflers are used to reduce noise from the exhaust of air but do not contribute to motion in any form. Thus, the cylinder stands out as the correct answer, as it directly creates the linear movement essential for various tasks in pneumatic systems.