Final answer:
The question deals with the deceleration and vertical velocity concepts in physics, tied to the altitude changes of a plane during turbulence, expressed as an absolute value.
Step-by-step explanation:
The question seems to be pertaining to the concept of deceleration and its representation in physics, specifically within the context of a plane's altitude changes during turbulence. When we talk about altitude change expressed as an absolute value, we can relate it to the concept of vertical velocity and acceleration. An example of this is when the plane lands with an initial velocity of 70.0 m/s and slows to a final velocity of 10.0 m/s and the acceleration is negative since it is opposite the direction of the positive velocity. Similarly, in the case of a coin dropped in the plane, the negative square root of the acceleration due to gravity is chosen because the velocity is directed downwards.
When a plane experiences a decrease in altitude due to turbulence, the altitude change can be measured as the difference between the starting and ending altitudes, which is independent of the direction of the change; hence, it's expressed as an absolute value. The acceleration mentioned, -15 × 10² m/s², implies a significant force acting upon the falling objects within the plane, likely indicating a rapid decrease in altitude during the turbulence.