Laminar flow of a liquid through a pipe tends to become turbulent when ____.
Correct answer D. the flow speed exceeds a certain critical value
Subject / 480 questions
MDCAT ECAT Physics MCQs
Page 18 of MDCAT ECAT Physics multiple-choice questions with answers. Tap an option to check yourself.
Page 18 of 24
- Electromagnetic Induction 30
- Fluid Dynamics 30
- Electrostatics 30
- Electronics 30
- Electromagnetism 30
- Current Electricity 30
- Work and Energy 30
- Waves 30
- Vectors and Equilibrium 30
- Nuclear Physics 30
- Dawn of Modern Physics 30
- Thermodynamics 30
- Rotational and Circular Motion 30
- Atomic Spectra 30
- Alternating Current 30
- Force and Motion 30
Which feature is characteristic of turbulent flow?
Correct answer C. Irregular, changing motion with eddies and whirlpools
How does the viscosity of most liquids change as their temperature rises?
Correct answer C. It decreases
Advertisement
What is the SI unit of the coefficient of viscosity?
Correct answer B. N s m⁻²
The equation of continuity A₁v₁ = A₂v₂ for an incompressible fluid is a consequence of the conservation of ____.
Correct answer C. mass
Water flows at 1.5 m/s through a pipe of cross-sectional area 8.0 cm² which narrows to 2.0 cm². What is the speed of the water in the narrow section?
Correct answer A. 6.0 m/s
Water moves at 0.80 m/s in a pipe of diameter 4.0 cm. What is its speed where the diameter reduces to 2.0 cm?
Correct answer A. 3.2 m/s
A garden hose of internal radius 1.0 cm delivers water at 2.0 m/s. Approximately how long does it take to fill a 30 L bucket?
Correct answer A. 48 s
Blood flows through an aorta of cross-sectional area 3.0 cm² at an average speed of 0.30 m/s. What is the volume flow rate?
Correct answer D. 90 cm³/s
Advertisement
Why does a stream of water falling from a tap become narrower as it falls?
Correct answer D. Its speed increases, so by continuity its cross-sectional area must decrease
Bernoulli’s equation for a fluid flowing along a streamline is based on the principle of conservation of ____.
Correct answer B. energy
For a small sphere falling through a viscous fluid, how does its terminal velocity depend on its radius r?
Correct answer D. It is proportional to r²
A tiny oil droplet falls through air with a terminal velocity of 2.0 mm/s. What is the terminal velocity of a similar droplet of three times the radius?
Correct answer A. 18 mm/s
A dust particle of radius 1.0 × 10⁻⁵ m moves at 0.50 m/s through air of viscosity 1.8 × 10⁻⁵ Pa s. What is the Stokes drag force on it?
Correct answer C. 1.7 × 10⁻⁹ N
A glass sphere of radius 1.0 mm and density 2500 kg/m³ falls through glycerine of density 1260 kg/m³ and viscosity 1.5 Pa s. What is its terminal velocity (g = 9.8 m/s²)?
Correct answer D. 1.8 mm/s
Advertisement
A falling ball of mass 0.050 kg has reached its terminal velocity in air. Ignoring upthrust, what is the drag force acting on it (g = 9.8 m/s²)?
Correct answer B. 0.49 N
A skydiver falling at terminal velocity changes from a spread-eagle position to a head-down position. What happens to her terminal velocity?
Correct answer B. It increases because the drag at any given speed is reduced
Which statement correctly describes steady (streamline) flow of a fluid?
Correct answer B. The velocity of the fluid at any given point does not change with time
A wheel starts from rest with a constant angular acceleration of 2 rad/s². Through what angle does it turn in 10 s?
Correct answer C. 100 rad
A small steel ball falling through a viscous liquid reaches its terminal velocity when ____.
Correct answer A. the net force on it becomes zero