List of top Mechanical Engineering Questions

Match List I (Non-dimensional number) with List II (It is the ratio of):

LIST I	LIST II
A. Reynold’s Number	III. Inertia force to viscous force
B. Mach Number	I. Inertia force to elastic force
C. Froude’s Number	II. Inertia force to gravity force
D. Weber’s Number	IV. Inertia force to surface tension force

Choose the correct answer from the options given below:

Match List I (Non-Dimensional Number) with List II (Formula):

LIST I	LIST II
A. Nusselt Number	I. \( \mu C_p / k_f \) (where \( k_f \) is thermal conductivity of fluid)
B. Biot Number	II. \( hL / k_s \) (where \( k_s \) is thermal conductivity of solid)
C. Prandtl Number	III. \( h / \rho C_p \)
D. Stanton Number	IV. \( hL / k_f \) (where \( k_f \) is thermal conductivity of fluid)

Choose the correct answer from the options given below.

Match List I with List II:

LIST I (Component)	LIST II (Equipment used in)
A. Draft Tube	III. Francis Turbine
B. Thermostatic Expansion Valve	II. Cold Storage
C. Feed Water Heater	I. Thermal Power Plant
D. Automatic Expansion Valve	IV. Central AC Plant

Choose the correct answer from the options given below:

Match List I with List II:

LIST I	LIST II
A. Involute Gear	I. Variable Pressure Angle
B. Cycloidal Gear	II. Constant Pressure Angle
C. Gyroscope	III. Sensitivity
D. Governor	IV. Stability

Choose the correct answer from the options given below:

In a plane stress system, two principal stresses are 785 N/mm² and 115 N/mm². If the system just causes yielding, what is the uni-axial yield stress of the material according to the Von Mises criterion:

Consider the following statements
(A) For the two shafts connected in parallel, the angle of twist of each shaft is same.
(B) For the two shafts connected in series, the shear stress in each shaft is same.
(C) The shear stress in a circular shaft under torsion varies linearly.
(D) The shear stress at the centre of a circular shaft under torsion is zero.
Choose the correct answer from the options given below:

Under ideal conditions in drawing operation maximum possible reduction of area in one pass is:

Consider the following statements A Frictional force is dependent of area of contact B Frictional force acts in tangential direction to the surface in contact C Maximum value of static friction is known as limiting friction D Dynamic friction is also known as kinetic friction

A ball is thrown vertically upward with velocity 5 m/sec It takes 10 sec for its upward journey The time taken by the ball for its downward journey is

Forces whose line of action passes through a common point are known as

Three identical gears A B and C are used in power transmission. Gear A and C are input and output gears Gear B is an idler gear connecting A and C. The gear which is subjected to reversed nature of stress is

A specimen is subjected to a stress which follows sinusoidal variation with respect to the time from minimum zero value to a maximum value \(+\sigma\):

1. Mean value of Stress = 0
2. Amplitude of Stress = \( \sigma / 2 \)
3. Nature of Stress = Repeated Stress
4. Nature of Stress = Fluctuating Stress

Choose the correct answer from the options given below:

The coefficient of restitution of a perfectly plastic impact is equal to:

Consider the following statements about shear stresses in beams A The shear stress at neutral axis of a rectangular section is the maximum stress B The shear stress variation across a rectangular section is parabolic C The shear deformations are small as compared to bending deformation D The shear centre is also known as centre of moment

The type of brake in which frictional force assists in applying the brakes is termed as

A shaft is subjected to Bending Moment (\( M \)) and Torsional Moment (\( T \)), the equivalent torsional moment in the shaft is:

A solid disc of mass \( m \), radius \( r \) is resting on a horizontal smooth surface. A spring of stiffness \( k \) is connected to the disc at distance \( e \) directly above the centre of the disc. Another end of the spring is connected to the vertical wall. For small angular displacement of the disc, the natural frequency of the system in radians per second will be:

Given below are two statements:
Statement (I): Flywheels are used to control the fluctuations in speed of machines arising from external sources.
Statement (II): Governors are used to control the fluctuations in speed of machines arising from internal sources.
In light of the above statements, choose the most appropriate answer from the options given below.

The undamped natural frequency of system is 80 rad/sec. A damper is provided in the system having damping factor 0.7. The damped natural frequency of the system in rad/sec will be:

An aeroplane is making a left turn as viewed by an observer from the rear of the plane The engine rotor of the plane are running in clockwise sense when viewed from the rear side The gyroscopic effects tend to

The instantaneous centre of a sliding body moving on a stationary curved surface lies at

Assertion (A): In heating and dehumidification of air, relative humidity of air decreases.
Reason (R): Sensible heating causes enthalpy to decrease.
In light of the above statements, choose the correct answer from the options given below.