Mechanical Aptitude Fluid Dynamics Principles Questions and Answers Flashcards
6 cards from real MECHANICAL APTITUDE practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Mechanical Aptitude Fluid Dynamics Principles Questions and Answers flashcards as text
Which factor does NOT directly affect the buoyant force on a submerged object?
Answer: Mass of the object
Buoyant force equals the weight of displaced fluid (fluid density x volume x gravity), so the object's mass does not directly determine buoyancy.
Water flows through a horizontal pipe at a steady rate. If the pipe diameter is tripled, by what factor does the flow velocity change assuming the same volumetric flow rate?
Answer: Decreases to 1/9
Area increases by the square of the diameter ratio (3^2 = 9), so velocity decreases to 1/9 of the original to maintain the same flow rate.
A siphon is used to transfer water from a higher tank to a lower tank. What primarily drives the flow?
Answer: Atmospheric pressure and gravity
A siphon works because atmospheric pressure pushes fluid up the shorter leg while gravity pulls it down the longer leg, sustaining continuous flow.
If the Reynolds number for flow in a pipe exceeds approximately 4,000, the flow is generally classified as what?
Answer: Turbulent
A Reynolds number above approximately 4,000 indicates fully turbulent flow in pipe systems.
A fire truck pumps water through a hose and out a nozzle. Why does the water exit the nozzle at a much higher speed than it travels through the hose?
Answer: The nozzle has a smaller cross-sectional area than the hose
The nozzle's smaller area forces the same volume of water through a tighter space, increasing velocity according to the continuity equation.
Two identical containers are filled with different fluids: one with mercury and one with water. Which has greater pressure at the bottom?
Answer: The mercury container
Hydrostatic pressure equals fluid density times gravity times depth, and mercury is about 13.6 times denser than water, so it exerts far greater pressure at the same depth.