Chapter 41 · 788 practice MCQs
MDCAT Fluid Dynamics MCQs 2026 | Bernoulli & Continuity
What is conserved in a pipe is volume per second, not speed. Unit 5 is continuity, Bernoulli, Venturi, Stokes and terminal velocity — roofs lift because the air above them is faster, not because of a slogan.
·6 min read·Usman Ubaid
What MDCAT 2026 asks in Unit 41 Fluid Dynamics
PMDC Unit 5 is the fluid chapter MDCAT actually examines: moving fluids, not a reprint of hydrostatics. Continuity says for an incompressible flow. Halve the radius and speed is four times, not two, because area is ².
Bernoulli then trades that speed for pressure: P + h + ½ ² is constant along a streamline. A constriction (Venturi) is fast and low-pressure — that is the suck. Stokes’ drag 6 ηrv plus upthrust plus weight set terminal velocity. Ideal fluid means incompressible, non-viscous, streamline; blood is not ideal, but the exam still uses the model.
Twenty labs: a pipe that narrows, a roof, a sphere falling into a terminal speed.
- Continuity: Radius ÷ × 4.
- Bernoulli: faster fluid, lower pressure. Aeroplanes and roofs are the same sentence.
- Venturi: a throat with a side tube. Pressure drop is the measurement.
- Stokes: = 6 ηrv. Terminal velocity when + upthrust.
- Ideal fluid assumptions — and when the stem tells you they fail.
Often-asked Fluid Dynamics MCQ patterns
These are the Fluid Dynamics ideas that keep coming every year with new numbers.
- Radius × ½, speed × 2 — wrong. Area scales as r².
- Pressure rises in a constriction — the opposite of Bernoulli.
- Terminal velocity without upthrust, as if the sphere fell in vacuum with only Stokes.
- Using Bernoulli on a viscous, turbulent mess without the disclaimer.
Worked Fluid Dynamics numericals (
Work these on paper first. Then open the Unit 41 quiz — the same numbers are in the questions, with wrong options built from the usual mix-ups.
Water in a pipe of radius flows at . The pipe narrows to . Speed in the throat?
. Half the radius is a quarter the area, four times the speed.
Same height, speed doubles. What happens to pressure?
- P + ½ ² is constant if h is fixed.
- v × × 4. Pressure must fall to keep the sum constant.
Pressure drops. Faster, lower P — that is the whole of Bernoulli at constant height.
Fluid Dynamics traps that steal the mark
A good option is a true sentence about the wrong quantity. If you miss, the quiz names the mix-up on the option you actually picked.
- Scaling speed with radius instead of radius squared.
- Saying pressure rises in a constriction.
- Forgetting upthrust in terminal velocity.
- Using Bernoulli on a viscous, turbulent mess without the disclaimer.
- Mixing mass-flow and volume-flow when density is not constant (MDCAT usually takes water as incompressible).
Fluid Dynamics formula sheet for MDCAT 2026
Write these until they are cheaper than thinking. Then open the Fluid Dynamics quiz and make the picture agree.
- from + upthrust
How to practise Unit 41 Fluid Dynamics MCQs
On a pipe question, write Av first, then Bernoulli. Continuity gives v; Bernoulli gives P.
On a falling-sphere question, draw three arrows: weight down, upthrust up, Stokes up. Terminal is when they cancel.
Sit Fluid Dynamics after Motion (Newton) and Energy (Bernoulli is energy per volume).
Choose topics and a test length up to 180 from the 788-question bank. Tutor Mode explains each selection; Timed Exam reveals explanations on submission. Use the complete review to revise mistakes and download your results.
FAQ
Common questions
Are Bernoulli and Venturi in the MDCAT Fluid Dynamics quiz?
Yes. Unit 5 walks continuity into Bernoulli into a Venturi, then Stokes and terminal speed.
Why does speed quadruple when radius halves?
Area is ². Half the radius is a quarter the area, so v must rise fourfold to keep Av constant. Continuity follows conservation of mass for steady flow. The simple form assumes an incompressible fluid; do not apply the radius ratio directly without squaring it to get area.
Does faster air mean higher pressure?
No. Bernoulli: faster fluid, lower pressure. That is why a roof lifts and a Venturi sucks. Compare points at the same height along a streamline under the ideal-flow assumptions. Bernoulli's equation includes pressure, kinetic and gravitational terms, so a height change must also be included.
What is terminal velocity in MDCAT?
The constant speed of a sphere (or drop) when weight is balanced by viscous drag plus upthrust. At terminal speed the acceleration is zero because the forces balance; the object is still moving. Increasing viscosity generally lowers terminal speed for the same sphere in the Stokes-flow regime.
Is this unit hydrostatics or dynamics?
Dynamics — moving fluids. Continuity, Bernoulli, Venturi, Stokes. Not a Pascal-only chapter.
How many Fluid Dynamics MCQs are available on DIFF. MDCAT?
The current Fluid Dynamics question bank contains 788 practice MCQs across 10 topics. This is the bank size, not the length of one test. Choose your topics and a question count from 1 to 180, limited by the questions available in those topics.
Which topics does the Fluid Dynamics quiz cover?
The selectable topics are Terminal Velocity, Fluid Drag, Fluid Flow, Continuity Equation, Bernoulli's Principle, Drag & terminal, Applications, Flow, Continuity, Bernoulli. Use Select all for a broad chapter drill, Clear to start a focused selection, or choose individual topics. Questions are drawn from your chosen topics, so you can target a weak concept before returning to a wider test.
How do I build a custom Fluid Dynamics test?
Open the chapter builder, select one or more topics, enter your question count, and choose Tutor Mode or Timed Exam. The available-question total updates with your selection. Start Test generates a shuffled drill; you do not have to follow a fixed Quiz 1 or Quiz 2 sequence.
What is the difference between Tutor Mode and Timed Exam?
Tutor Mode gives feedback and an explanation after you choose an option, and you can change or clear that choice. Timed Exam runs a countdown and keeps explanations hidden until submission. Both modes let you move between questions, use the paper map, and submit for a complete review.
How do I review and download my Fluid Dynamics quiz?
Select Submit Quiz, then Submit & View Explanations. The review includes every question in your test, all options, your selection, the marked correct answer when a key is available, and the explanation. Download PDF saves a paginated review; Download Review saves an HTML copy you can open in a browser. The review also includes DIFF. MDCAT community links.
How should I use Fluid Dynamics MCQs to improve?
Start with a short tutor drill on one of these topics: Terminal Velocity, Fluid Drag, Fluid Flow. Read the explanation for incorrect and uncertain answers, revise the relevant textbook section, and retry before taking a timed drill. Compare your reasoning with the answer key rather than memorising the option letter.
Ready to sit Unit 41 Fluid Dynamics — 788 MCQs, 788 labs?