Final answer:
The scale reading in an elevator varies based on its motion: greater than the weight when accelerating, equal to the weight when moving at a constant speed or stationary.
Step-by-step explanation:
The scale reading in the elevator will vary depending on whether the elevator is accelerating, moving at a constant speed, or decelerating. When the elevator accelerates upward at a rate of 1.20 m/s², the scale reading will be greater than the person's weight. This is because the scale must exert an upward force greater than the person's weight in order to accelerate them upward. On the other hand, when the elevator moves upward at a constant speed of 1 m/s or is stationary, the scale reading will be equal to the person's weight.