Final answer:
The net force acting on an elevator that is traveling upward and slowing down must be pointed downward, as this deceleration indicates that there is a net force opposite to the elevator's upward motion.
Step-by-step explanation:
If an elevator is traveling up and slowing down, the net force acting on it must be pointed downward (Option B). This is because for the elevator to slow down while moving upward, there must be a net force opposite to the direction of motion, which means a downward force. When the elevator is accelerating, either upward or downward, the net force must be in the direction of acceleration. For example, if the elevator is accelerating upward, the net force is upward, and when it's accelerating downward (a negative acceleration), the net force is downward. If the elevator reaches a constant upward velocity, the acceleration is zero and thus the net force is zero, resulting in a scale reading equal to the person's weight. However, while slowing down (decelerating) as it moves up, the acceleration is negative (pointing downward), so the net force is also downward.