When checking the car door closing force, the doors should be positioned between what fractions of their travel?

When checking the car door closing force, it is essential to ensure that the doors are positioned at an optimal point in their travel to accurately assess how much force is required to close them. The correct choice highlighting this position is between 1/3 and 2/3 of their overall travel.

This range is significant because it allows for an examination of the door's closing dynamics when the door is not fully opened or fully closed, where the closing force measurements could be skewed. By positioning the doors within this specific fraction of their travel, the test simulates conditions where the door would typically meet resistance, such as encountering an obstacle as it closes.

The choice of this range helps maintain a balance where the door is still under the influence of gravity and mechanical resistance, making it a realistic evaluation of the closing force in real-world scenarios. This ensures safety compliance and efficient operation of the elevator system.