Calculate pressure from a perpendicular load
Compare the same block resting on different faces and share a chair’s load across circular feet. Match the force carried by one contact to that contact’s area.
AP Physics 1 · Unit 8 · Fluids
Pressure Practice Problems
Connect contact area and liquid depth to pressure, then use pressure differences to predict net forces.
12 questions6 conceptual · 6 calculation
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What you’ll practice
Use the right force, area, depth, and pressure reference
Measure density and pressure at depth
Subtract a container’s empty mass before using equal fill volumes to find an unknown density. Measure a cork’s depth below its own water surface and compare containers of different widths.
Find net forces and layered-liquid pressures
Use outside minus inside absolute pressure across a vacuum opening or submerged suction cup. Add the separate oil and water contributions to find bottom gauge and absolute pressure.
A question from this set
Which face produces the greatest pressure?
A uniform rectangular block has edge lengths 3.00 cm, 4.00 cm, and 6.00 cm. Face A is 4.00 cm × 6.00 cm, face B is 3.00 cm × 4.00 cm, and face C is 3.00 cm × 6.00 cm. Rank the pressure the same block exerts on a table when resting on each face, greatest first.
Try it in the practice setKey ideas
Separate a pressure value from a pressure force
Pressure has a value; surface forces have directions
A stationary liquid exerts force perpendicular to a contacted surface. Equal-depth patches have equal pressure even when one is on a horizontal bottom and the other is on a vertical wall.
A reference pressure changes the reading
Absolute pressure is measured from vacuum. Gauge pressure subtracts the surrounding atmosphere, so a chamber below atmospheric pressure has a negative gauge reading while its absolute pressure remains nonnegative.
See the physics
Compare native contact reactions and fluid-field measurements
After an answer attempt, run gravity-driven floor contacts, fill equal-volume calibration containers, or scan a pressure probe through stationary water and oil. Compare alternate contact areas, extra chair feet, wider containers, deeper cups, and thicker oil layers. Recorded graphs and readouts reveal the measured quantities.
Use a hint for a starting point or open a worked solution to follow the reasoning. Your progress saves in this browser, so you can return to unfinished questions.
Ready for pressure?
Begin with a conceptual question, then work through the calculations.