What term describes a change in speed without a change in direction during flight?

Linear acceleration refers to the change in speed of an aircraft without altering its direction. This is a fundamental concept in physics and aerospace mechanics, highlighting how an aircraft can increase or decrease its velocity while maintaining a straight flight path. When an aircraft speeds up, it experiences positive linear acceleration, and when it slows down, the acceleration is negative.

In contrast, angular acceleration pertains to changes in the rotational speed of an object around a pivot point, which isn’t applicable to the changes in linear speed of an aircraft. Radial acceleration is specifically related to an object moving in a circular path, pointing towards the center of that path – it involves a change in direction. Centripetal force, meanwhile, is the force that keeps an object moving in this curved path, not a description of a change in speed. Thus, linear acceleration is the most accurate term for describing a speed change without any alteration in direction during flight.