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Pressure can be expressed in all of the following units except one. Which one is incorrect?

A. torr
B. dyn/cm³
C. N/m
D. kg/ms²

User Brian Luft
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1 Answer

5 votes

Final answer:

Option D, kg/ms², is not a correct unit of pressure, as pressure is defined as the force applied per unit area, and this unit incorrectly uses mass rather than force.

Step-by-step explanation:

The question concerns the unit of measurement that is not a correct expression of pressure. Pressure can indeed be expressed in several units, including the pascal (Pa), which is the SI unit of pressure (1 Pa = 1 N/m²). But when we look at the options given, most of them are valid units of pressure. A torr is a unit derived from millimeters of mercury (mmHg) and relates to atmospheric pressure, so it is indeed a unit of pressure. Dyn/cm² is also a correct unit of pressure known as the barye, and it's a CGS unit (1 dyn/cm² = 0.1 N/m²). N/m (newton per square meter) is essentially another way of saying pascal (Pa), so this is a correct unit for pressure as well. The confusion comes with the option D, kg/ms², which is not a correct unit of pressure. Pressure is the force applied per unit area, and while the kg/ms² has units of mass (kg), time (s), and acceleration (m/s²), it doesn’t correspond to any accepted unit of pressure. In terms of units, pressure should combine the force (not mass) with area in a way that is consistent with the definition of the pascal. Therefore, the correct answer is D, kg/ms².

User Drew Moore
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7.3k points