Question #132
The density of hydraulic oil at a temperature below 0°C:
Gęstość oleju hydraulicznego w temperaturze ujemnej:
a
decreases
maleje
b
increases
wzrasta
Correct answer
c
temperature has no effect on oil density
temperatura nie ma wpływu na gęstość oleju
d
remains unchanged
pozostaje bez zmian
Why?
As oil cools, it contracts, so the same mass occupies less volume and its density (gęstość) increases. Answers claiming that temperature has no effect are wrong. Viscosity (lepkość), meaning resistance to flow, also increases, but it is a different property.