Ergonomics & Human Factors Engineering Flashcards

What is the purpose of a time-and-motion study in industrial engineering?

Answer: To determine standard times for tasks by observing and timing work elements

Time-and-motion studies break jobs into elements, time them with a stopwatch, apply performance ratings, and add allowances to establish standard times.

In human reliability analysis, what does a Human Error Probability (HEP) of 0.01 mean?

Answer: There is a 1% probability of human error on a given task

An HEP of 0.01 means there is a 1-in-100 probability that an operator will make an error when performing a specific task under defined conditions.

Which principle of motion economy suggests that both hands should begin and end their motions simultaneously?

Answer: Principle of simultaneous hand motions

The principle of simultaneous hand motions reduces idle time and cognitive load by synchronizing the start and finish of both hands' movements.

What is 'vigilance decrement' in human factors engineering?

Answer: The decline in detection performance during prolonged signal-detection tasks

Vigilance decrement refers to the decrease in an operator's ability to detect rare signals as the duration of sustained attention monitoring increases.

Which body posture is most associated with lower back disorder risk on the job?

Answer: Sustained forward trunk flexion combined with twisting

Combined trunk flexion and rotation increases spinal compressive and shear forces substantially, raising the risk of intervertebral disc injury.

In display design for control rooms, what does the 'primary zone' of a visual display refer to?

Answer: The central field of view typically within ±15° from line of sight

The primary zone (±15° from the line of sight) is where frequently consulted displays should be located to minimize eye and head movement.