Question 3
Which plastic is most suitable for the gears inside a kitchen food mixer?
Not quite. Acrylic is rigid but brittle, so the teeth on your gears would chip.
Not quite. ABS is the material you would use for the mixer’s housing, not the gears inside it.
That is it. Step through the hints below to see why.
Not quite. You would choose polycarbonate for impact strength and transparency (guards, lenses), not wear.
A food mixer with its gears inside the housing. Each test shows the plastic doing its job in the mixer, or failing at the gears.
The gears need: wear resistance and low friction.
Testing () :
The acrylic gears jam and a tooth chips off. Acrylic is rigid but brittle. Not this one.
ABS lights up the housing, not the gears. It is the material for the mixer’s housing. Not this one.
The nylon gears turn smoothly. Nylon is tough, wear resistant and low friction, so it is the gear plastic. This is the one.
Polycarbonate lights up a clear guard, not the gears. It is chosen for impact strength and transparency, not wear. Not this one.
Nylon is the gear plastic. It is tough, wear resistant and low friction.
Gear teeth slide against each other constantly, so wear resistance and low friction decide the choice.
Nylon is the gear plastic. It is tough, wear resistant and low friction.
The past QCAA questions this one was modelled on
Only mark this done when you could do it without help. Reading the solution does not count.
A Tangent Tuition mock exam question. It is not a past QCAA question, and Tangent Tuition is not affiliated with the QCAA.
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