CEA Industrial Ergonomics 2 — Questions and Answers
Question 1: Which NIOSH equation variable accounts for the horizontal distance of the load from the worker's body?
- Frequency Multiplier (FM)
- Horizontal Multiplier (HM) (Correct answer)
- Asymmetry Multiplier (AM)
- Coupling Multiplier (CM)
Correct answer: Horizontal Multiplier (HM)
The Horizontal Multiplier (HM) in the NIOSH Lifting Equation penalizes lifts where the load is held far from the body, increasing spine loading.
Question 2: In a push/pull task, which force measurement is most critical for ergonomic evaluation?
- Sustained push force only
- Initial peak force and sustained force (Correct answer)
- Sustained pull force only
- Final release force
Correct answer: Initial peak force and sustained force
Both the initial peak force (to break inertia) and sustained force (to keep the load moving) must be measured and compared against limits.
Question 3: What does the term 'anthropometric variability' mean in workstation design?
- Variation in worker productivity over a shift
- Natural range of human body dimensions across a population (Correct answer)
- Differences in cognitive load between tasks
- Variation in muscle fatigue rates
Correct answer: Natural range of human body dimensions across a population
Anthropometric variability refers to the natural differences in body dimensions (height, reach, etc.) across a worker population that must be accommodated in design.
Question 4: A conveyor belt height that is too low for assembly work primarily causes which ergonomic risk?
- Excessive neck extension
- Prolonged trunk flexion (Correct answer)
- Wrist radial deviation
- Shoulder abduction above 90°
Correct answer: Prolonged trunk flexion
A conveyor set too low forces workers to bend forward repeatedly or sustain trunk flexion, increasing lumbar spine loading.
Question 5: Which industrial scenario BEST illustrates a 'pinch grip' hazard?
- Carrying a box with both hands under it
- Gripping a screwdriver handle in the palm
- Holding a thin sheet metal blank between thumb and fingers (Correct answer)
- Pulling a rope hand-over-hand
Correct answer: Holding a thin sheet metal blank between thumb and fingers
A pinch grip occurs when thin objects are held between the fingertips and thumb, generating high tendon forces relative to power grip.
Question 6: What is the primary purpose of a job rotation program in ergonomics?
- Eliminate all repetitive tasks from the workplace
- Distribute cumulative musculoskeletal loading across different muscle groups (Correct answer)
- Increase worker productivity per hour
- Reduce the need for personal protective equipment
Correct answer: Distribute cumulative musculoskeletal loading across different muscle groups
Job rotation spreads repetitive exposures across different muscle groups and body regions, reducing cumulative loading on any single structure.
Question 7: When evaluating manual assembly work, 'cycle time' is important because shorter cycles typically mean:
- Lower force requirements per motion
- Higher repetition rates that increase cumulative injury risk (Correct answer)
- Fewer awkward postures per hour
- Greater worker autonomy over pace
Correct answer: Higher repetition rates that increase cumulative injury risk
Shorter cycle times mean the same motions are repeated more frequently per hour, increasing the repetition rate and cumulative musculoskeletal exposure.
CEA Industrial Ergonomics 2
Which NIOSH equation variable accounts for the horizontal distance of the load from the worker's body?