IB Design Technology practice questions.

A design team records the body dimensions of a user group and also measures how quickly the same users tire while operating a hand tool. Which statement describes the relationship between anthropometrics and ergonomics?

• Anthropometrics is a subset of ergonomics, which also covers physiology and psychology
• Ergonomics is a subset of anthropometrics, which also covers reach and clearance data
• The two terms name the same field of study and can be used interchangeably here
• Anthropometrics studies fatigue, whereas ergonomics studies static body measurements

Answer: Anthropometrics is a subset of ergonomics, which also covers physiology and psychology

Anthropometrics supplies the body measurements, but ergonomics is the wider study of the whole user-product interaction, including physiological load and cognitive demand. Treating the two words as synonyms is the most common error in this subtopic.

A hospital ward is buying overbed tables for patients who eat sitting up in bed. The patients range from small older women to tall adult men, and each table stays with one patient for several days. Which approach to the table height gives the best fit for this user population?

• Fixed at the 50th percentile seated elbow height
• Fixed at the 95th percentile seated elbow height
• Adjustable from the 5th to the 95th percentile seated elbow height
• Fixed at the 5th percentile seated elbow height, with a cushion supplied for taller patients

Answer: Adjustable from the 5th to the 95th percentile seated elbow height

Where one product must serve a wide spread of body sizes and stays with each user long enough to be set up, adjustability across the 5th to 95th percentile range is the standard user-centred solution. Any fixed value, including the 50th percentile, leaves a large part of the population working at the wrong height.

A cordless vacuum cleaner runs only when it detects an authorised filter unit, and the maker withdraws that filter from sale two years after launch although the motor, battery and body are unaffected. This design decision is best classified as:

• Functional obsolescence caused by component wear
• Technological obsolescence
• Planned obsolescence
• Design for disassembly

Answer: Planned obsolescence

The cleaner is still fully capable of working, so its life is ended by a deliberate design and supply decision rather than by wear, which is planned obsolescence. Functional obsolescence follows genuine wear, and design for disassembly has the opposite intent because it extends useful life through repair and material recovery.

A full section is taken through an assembly along the length of a solid shaft and of the bolt that retains it, so that the cutting plane runs down the axis of both. How are the shaft and the bolt shown in that sectional view?

• Hatched in the same direction as the housing around them
• Left unhatched and drawn as outside views
• Hatched at 30 degrees so that they read as fixings
• Omitted from the section and shown on the plan only

Answer: Left unhatched and drawn as outside views

Shafts, bolts, nuts, pins, keys, ribs and webs are conventionally not sectioned when the cutting plane runs along their length, because hatching them adds nothing and hides their form. They are hatched only where the plane cuts across their axis.