PRACTICE COLLECTION / 39 PROBLEMS
Fluids
Balance pressure, buoyancy and steady flow. Each problem includes progressive hints, guided reasoning and a question to test the idea again. Problems marked “Free sample” are complete for everyone; membership opens the rest.
LEARN BEFORE YOU PRACTISE
Build the reasoning first.
Pressure, floating and fluid support
Derive pressure from equilibrium, then use it to explain buoyancy and support readings.
16 worked examples · 12 checks →Continuity and energy in flowing fluids
Track mass first, then connect pressure, speed and height along a valid flow model.
9 worked examples · 8 checks →Elastic response and measuring Young’s modulus
Separate material stiffness from specimen geometry, then infer a modulus from a controlled extension experiment.
6 worked examples · 8 checks →Surface tension, curved interfaces and capillary rise
Count interfaces and connect boundary forces, surface work, pressure jumps and wetting.
5 worked examples · 9 checks →Capillarity and curved interfaces
Read the meniscus, count the interfaces and connect pressure, height and surface energy.
7 worked examples · 6 checks →Viscosity, terminal motion and flow regimes
Choose the drag model, balance forces and test the Reynolds number before trusting a speed.
6 worked examples · 8 checks →Viscous flow through pipes
Derive the velocity profile, track pressure losses and test what a change in radius really means.
8 worked examples · 6 checks →CONCEPTS IN THIS COLLECTION
PRACTISE AT YOUR PACE
Problems in this collection
39 problems · Showing 12
Fluids
A hatch responds to pressure difference
What is the magnitude of the resultant pressure force?
Apply a principleFluids
What is the net force on a submerged block?
What is the net force immediately after release?
Connect conceptsFluids
What happens when the pipe narrows?
What is the mean speed at the narrower section?
Apply a principleFluids
Walk down each column to one common level
What is the gauge pressure pg − pa?
Apply a principleFluids
Count curvature before multiplying
A factor of two needs a physical explanation: curvature and interface count are distinct.
Compare casesFluids
Separate depth from curvature
How much higher is the deeper bubble’s absolute gas pressure?
Compare casesFluids
Measure the missing wetting angle
What contact angle is consistent with this rise?
Find a missing quantityFluids
Read the sign at a depressed meniscus
What is liquid pressure just beneath the meniscus minus gas pressure above it?
Connect conceptsFluids
A height is not a tube length
What length along the tube lies between its crossing of the reservoir level and the meniscus?
Apply a principleFluids
Weight the speed by area
What is the volume flow rate?
Apply a principleFluids
Keep room above the water
What maximum cargo mass leaves at least 0.040 m of freeboard?
Apply a principleFluids
The same weight needs more volume
How much farther does it sink in the second liquid?
Compare cases12 of 39 shown