Which quantity is defined as the force per unit area exerted by a system on its surroundings?

Which quantity is defined as the force per unit area exerted by a system on its surroundings?

• A. Pressure
• B. Temperature
• C. Volume
• D. Density

Answer: (A)

Pressure is the force per unit area exerted by a system on its surroundings. It describes how strongly the system pushes on the surfaces it touches, with units of pascals (N/m^2). In fluids, pressure acts normal to surfaces and is the same in all directions at a point in a static fluid. Temperature measures average kinetic energy of particles, not force per area. Volume is the space the system occupies, and density is mass per unit volume. Therefore, pressure is the quantity that matches the description.

Pressure is the force per unit area exerted by a system on its surroundings. It describes how strongly the system pushes on the surfaces it touches, with units of pascals (N/m^2). In fluids, pressure acts normal to surfaces and is the same in all directions at a point in a static fluid. Temperature measures average kinetic energy of particles, not force per area. Volume is the space the system occupies, and density is mass per unit volume. Therefore, pressure is the quantity that matches the description.