Mechanical Engineering - MCQ Practice Questions

Bernoulli's equation applies to:

Water at 20°C flows through a pipe network. The dynamic viscosity of water at 20°C is approximately:

In a converging nozzle, as the cross-sectional area decreases, the velocity of incompressible flow:

A fluid with dynamic viscosity μ = 0.8 Pa·s and density ρ = 800 kg/m³ flows through a pipe. What is the kinematic viscosity?

For laminar flow in a circular pipe, the Hagen-Poiseuille equation gives volumetric flow rate as Q = πΔPd⁴/(128μL). This assumes:

Which of the following statements about boundary layers is correct?

For flow through an orifice, the discharge coefficient Cd is always:

For steady flow of an incompressible fluid through a variable area duct, which equation relates velocities at different sections?

A fluid undergoes viscous deformation with velocity gradient du/dy = 50 s⁻¹. For Newtonian fluid with μ = 0.1 Pa·s, the shear stress is:

A fluid with dynamic viscosity μ = 0.8 Pa·s flows between two parallel plates separated by 5 mm. If the velocity gradient is 100 s⁻¹, what is the shear stress in the fluid?

Which of the following fluids is classified as non-Newtonian?

A 300 mm diameter pipe reduces to 150 mm diameter. If velocity in the larger pipe is 1.5 m/s, what is the velocity in the smaller pipe, assuming incompressible flow?

For laminar flow in a circular pipe, the Hagen-Poiseuille equation gives discharge as Q = πΔPd⁴/(128μL). This is valid for Reynolds number:

In a convergent nozzle, which property increases as the flow accelerates?

In compressible flow, if Mach number M = 1.2, the flow is classified as:

In fluid mechanics, which of the following statements about Pascal's law is correct?

The continuity equation for incompressible flow states that A₁V₁ = A₂V₂. If water flows through a pipe that narrows from 100 mm to 50 mm diameter, the velocity ratio V₂/V₁ is:

According to Bernoulli's equation, which energy form is neglected when the fluid flow is at constant elevation in a horizontal pipe?

In centrifugal pump design, the impeller exit diameter D₂ and speed N (rpm) determine the peripheral velocity U₂ = πD₂N/60. For a pump with D₂ = 300 mm running at 1500 rpm, the peripheral velocity is:

Which of the following is the primary function of a key in mechanical design?