If you've blown up a balloon, pumped up a bike tire or used a vacuum cleaner you already have a lot of experience with pressure.

Pressure is the amount of force exerted by a fluid on a surface per unit of area. If the air pressure in a bike tire is 50 psi (pounds / square inch) then each square inch of the rubber inside the tire is experiencing 50 pounds of force (about 222 Newtons). And if we increase the pressure in any part of an enclosed fluid, the pressure increases by the same amount everywhere (known as Pascal's principle).

We're going to talk about atmospheric pressure (the air pressure around us) and the difference between absolute pressure and gauge pressure.

Finally, we'll learn how to describe the pressure in a fluid at different points, and how fluid pressure increases with depth due to the weight of the fluid above it.

Multiple-Choice Questions

Answers

Free-Response Questions

Fluids (previously in AP Physics 2)

Note: These are questions from AP Physics 2 exams before 2025. For some questions only parts of the question are relevant to the Fluids unit in AP Physics 1 as noted below.

• 2023 Q3 - - Tank of water with pipe and two blocks, fluids, forces, buoyant force, flow, Bernoulli's equation, continuity equation
• 2022 Q1 - - (Part a) Block in tank of water hanging from string, fluids, forces, FBDs, buoyant force
• 2021 Q2 - - (Parts b and c) Balloon held underwater, fluids, density, pressure, forces, buoyant force
• 2018 Q4 - - (Parts a and c) Boat carrying steel bars, fluids, forces, buoyant force, flow, continuity equation
• 2017 Q1 - - Water flowing through pipe, fluids, flow, continuity equation, Bernoulli's equation, conservation of energy, forces, FBDs, buoyant force

• Crash Course - Fluids at Rest
• What is Pressure?
• Michel van Biezen - Pressure in a Fluid
• Michel van Biezen - Gauge Pressure vs Total Pressure
• Michel van Biezen - Pascal's Principle: Hydraulic Pump
• Michel van Biezen - The Barometer
• Michel van Biezen - Pressure Gauge

• Organic Chemistry Tutor - Absolute Pressure vs Gauge Pressure
• Organic Chemistry Tutor - U Tube Manometers With Oil and Water
• Organic Chemistry Tutor - Pascal's Principle, Hydraulic Lifts
• Organic Chemistry Tutor - Water Pressure, Gauge Pressure, Blood Pressure

• Walter Lewin - Fluid Mechanics, Hydrostatics, Pascal's Principle, Atmosph. Pressure
• Walter Lewin - Hydrostatics, Archimedes' Principle, Bernoulli's Equation
• Hyperphysics - Fluids

• Pressure unit converter

If you've blown up a balloon, pumped up a bike tire or used a vacuum cleaner you already have a lot of experience with pressure.

Pressure is the amount of force exerted by a fluid on a surface per unit of area. If the air pressure in a bike tire is 50 psi (pounds / square inch) then each square inch of the rubber inside the tire is experiencing 50 pounds of force (about 222 Newtons). And if we increase the pressure in any part of an enclosed fluid, the pressure increases by the same amount everywhere (known as Pascal's principle).

We're going to talk about atmospheric pressure (the air pressure around us) and the difference between absolute pressure and gauge pressure.

Finally, we'll learn how to describe the pressure in a fluid at different points, and how fluid pressure increases with depth due to the weight of the fluid above it.

Multiple-Choice Questions