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
A pipe narrows from a 4-inch diameter to a 2-inch diameter. If water flows at 2 ft/s in the wider section, what is the approximate velocity in the narrower section?
Answer: 8 ft/s
By the continuity equation, reducing the diameter by half reduces the area by a factor of four, so the velocity increases four times from 2 ft/s to 8 ft/s.
Which principle explains why a shower curtain gets pulled inward when the water is running?
Answer: Bernoulli's principle
The fast-moving air created by the shower reduces pressure on the inside of the curtain, and higher outside pressure pushes it inward, which is explained by Bernoulli's principle.
A hydraulic system has a small piston with an area of 5 sq in and a large piston with an area of 50 sq in. If 20 lbs of force is applied to the small piston, what force is exerted by the large piston?
Answer: 200 lbs
By Pascal's principle, the force is multiplied by the ratio of piston areas: 20 lbs x (50/5) = 200 lbs.
What happens to the flow rate in a pipe if the fluid viscosity doubles while all other factors remain constant?
Answer: Flow rate is reduced by half
According to the Hagen-Poiseuille equation, flow rate is inversely proportional to viscosity, so doubling viscosity halves the flow rate.
A tank has two outlet holes at different heights. Which statement is correct about the water streams?
Answer: The lower hole produces a faster stream
By Torricelli's theorem, the exit velocity depends on the depth of fluid above the hole, so the lower hole has greater pressure and produces a faster stream.
In a venturi meter, what happens at the narrowest section of the tube?
Answer: Pressure decreases and velocity increases
As the cross-section narrows, fluid velocity increases and pressure decreases according to Bernoulli's principle.