Final answer:
The acceleration of an airplane landing on a runway traveling east is negative, indicating it is decelerating or slowing down, with an acceleration direction opposite to its velocity, which is west.
Step-by-step explanation:
When an airplane lands on a runway traveling east, the description of its acceleration involves understanding that it decelerates as it comes in for landing. This is quantified by saying that if we designate east as a positive direction, the plane's acceleration is negative, meaning it is accelerating in the opposite direction of its initial velocity, which is westward. Since the plane is slowing down, this negative acceleration is also referred to as deceleration. In physics, acceleration is defined as the rate of change of velocity over time, and it has both magnitude and direction. Therefore, a landing airplane, while moving eastwards, has an acceleration vector pointing westwards if it is slowing down.
In practice, when a plane lands and decelerates, this involves the actions of the pilots applying brakes, using reverse thrust, and deploying spoilers to reduce the plane's speed. These actions collectively contribute to the change in velocity and produce the negative acceleration necessary for the plane to come to a stop safely.