What is the term for motion in a straight line?

The term that defines motion in a straight line is linear motion. This concept specifically refers to the movement of an object along a straight path, meaning that the object does not change its trajectory or direction but continues to progress in one direction only.

In physics, linear motion is characterized by relationships between distance, velocity, and acceleration, all measurable quantities that represent motion along a straight line. It contrasts with other types of motion, such as rotational or circular motion, which involve changes in direction or the path taken by an object.

By understanding linear motion, one can apply various principles of mechanics to analyze and predict the behavior of objects under different forces and conditions. This knowledge is fundamental in many engineering applications, including mechanical systems, vehicle dynamics, and others that rely on the straightforward principles of movement along straight paths.