Pressure

Definition

Pressure is the force exerted per unit area. It is typically measured in Pascals (Pa) or atmospheres (atm).

5 Must Know Facts For Your Next Test

1. Pressure in a fluid at rest is isotropic, meaning it acts equally in all directions.
2. The pressure at a depth $h$ in a fluid of density $\rho$ is given by $P = P_0 + \rho gh$, where $P_0$ is the surface pressure and $g$ is the acceleration due to gravity.
3. In static equilibrium, the sum of forces and torques on any part of a system must be zero, which affects how pressure distributes.
4. Gauge pressure is the pressure relative to atmospheric pressure, while absolute pressure includes atmospheric pressure.
5. The concept of buoyancy is related to pressure differences within a fluid, leading to an upward force on objects submerged.

Review Questions

• What equation represents the relationship between depth and pressure in a fluid?
• How does gauge pressure differ from absolute pressure?
• What principle explains why an object floats or sinks based on fluid pressures?

Related terms

Stress:

The internal force per unit area within materials that arises from externally applied forces.

Strain:

The deformation or displacement per unit length resulting from stress.

Buoyancy:

The upward force exerted by a fluid on an immersed object, equal to the weight of the displaced fluid.