Which type of pressure is described as existing in a confined space and not causing motion?

• A. Impact pressure
• B. Static pressure
• C. Relative pressure
• D. Absolute pressure

Answer: (B)

Static pressure is the pressure a fluid exerts on surfaces when there is no movement relative to the measurement point. In a confined space, the fluid molecules press in all directions on the walls without driving a flow, so this pressure exists without causing motion. When the fluid moves, some of the pressure comes from its motion (dynamic or impact pressure), and the total pressure would be higher if the flow were brought to rest. Absolute pressure is the total pressure relative to a vacuum, while gauge (relative) pressure is the pressure relative to ambient. So the description of pressure that exists in a confined space and does not cause motion aligns with static pressure.