The Properties of Fluids: More Practice

Pressure: Student Success Criteria I can solve problems and conduct an investigation related to the relationships between force, area, pressure, and volume.

An Introduction to Pressure SPH4C

Pressure Pressure is defined as the magnitude of the force per unit area:

Pressure Pressure therefore has units of N/m 2

Pressure Pressure is defined as the magnitude of the force per unit area: Pressure therefore has units of N/m 2, or pascals (Pa).

1 pascal 1 Pa is approximately equal to the pressure exerted by a single sheet of newspaper spread out on the floor.

1 pascal 1 Pa is approximately equal to the pressure exerted by a single sheet of newspaper spread out on the floor. Most pressures are therefore given in kilopascals (kPa): 1 Pa = kPa

Example A crate is 2.0 m long and 1.0 m wide. The weight of the crate is 5.2 x 10 3 N. What pressure does the crate exert on the floor?

Example

Example

Example

Atmospheric pressure The weight of the layers of air above us exerts a pressure.

Atmospheric pressure Standard atmospheric pressure at sea level is kPa (or 1 atmosphere). This instrument used to measure air pressure is called a barometer.

Atmospheric pressure A drinking straw works by decreasing the air pressure inside the straw: the atmospheric pressure is then greater than that in the straw and forces the liquid to rise up in the straw.

Atmospheric pressure Atmospheric pressure decreases at higher altitudes as there is less air above you.

Atmospheric pressure Atmospheric pressure decreases at higher altitudes as there is less air above you. This can cause your ears to “pop” when the pressure inside your ears is greater than the pressure outside.

Water Pressure Similarly pressure will increase with increasing depth under water as you have more water above you.