The unit Pa is equivalent to which expression?

The unit Pa is equivalent to which expression?

• A. Pascal (Pa)
• B. Joule (J)
• C. Newton (N)
• D. Watt (W)

Answer: (A)

Pressure is force per unit area. In SI, one Newton of force applied over one square meter gives a pressure of one Pascal, so Pa is defined as one Newton per square meter. Writing that in base units, a Newton is kg·m/s^2, so a Pascal is kg/(m·s^2), which is the same as N/m^2. The Joule is a unit of energy (N·m), and the Watt is a unit of power (J/s), while the Newton is a unit of force, not pressure. So the expression for the unit Pa is N/m^2, and the unit name is Pascal.

Pressure is force per unit area. In SI, one Newton of force applied over one square meter gives a pressure of one Pascal, so Pa is defined as one Newton per square meter. Writing that in base units, a Newton is kg·m/s^2, so a Pascal is kg/(m·s^2), which is the same as N/m^2. The Joule is a unit of energy (N·m), and the Watt is a unit of power (J/s), while the Newton is a unit of force, not pressure. So the expression for the unit Pa is N/m^2, and the unit name is Pascal.