Fluid Dynamics — A/L Physics

How do I practise Fluid Dynamics?

1 question with a worked solution

1. Water flows steadily through a horizontal pipe of non-uniform cross-section. At point A where the cross-sectional area is 20 cm², the speed is 2.0 m s⁻¹. What is the flow speed at a constriction B where the cross-sectional area narrows to 5.0 cm²?
   1. A) 8.0 m s⁻¹
   2. B) 10.0 m s⁻¹
   3. C) 4.0 m s⁻¹
   4. D) 0.5 m s⁻¹
   Check my answer

   Correct answer: A) 8.0 m s⁻¹

   For an incompressible fluid, the continuity equation applies: A₁ v₁ = A₂ v₂. Therefore, v₂ = (A₁ / A₂) v₁ = (20 cm² / 5.0 cm²) × 2.0 m s⁻¹ = 4 × 2.0 m s⁻¹ = 8.0 m s⁻¹.

   Show worked solution

   Step 1: Apply equation of continuity: A₁ · v₁ = A₂ · v₂. Step 2: v₂ = (A₁ / A₂) · v₁ = (20 / 5.0) × 2.0 = 4 × 2.0 = 8.0 m s⁻¹. Answer: 8.0 m s⁻¹.
   Modelled on: the A/L Physics examination pattern

Get this auto-marked

Next in the syllabus

Where does Fluid Dynamics fit in the syllabus?

Unit 2.7 · Year 1 · Term 1