Which of the following is NOT a unit of pressure?

The correct choice highlights that Newtons are not a unit of pressure, but rather a unit of force. Pressure is defined as the amount of force applied per unit area. Therefore, common units of pressure, such as Pascal, Atmosphere, and PSI (pounds per square inch), express this relationship by measuring how much force is exerted over a specific area.

Pascal is defined as one Newton per square meter, showcasing a direct tie to both force (Newtons) and area (square meters). Atmosphere is an older measurement based on the average air pressure at sea level, meaning it also reflects force per unit area. PSI, popular in various engineering and everyday applications, directly conveys pressure in terms of pounds of force applied over a certain area represented in square inches.

In summary, while Pascal, Atmosphere, and PSI measure pressure through the relationship of force to area, Newtons solely measure force, underscoring why it is the correct answer to the question of which is not a unit of pressure.