List of top Mechanical Engineering Questions asked in Common University Entrance Test

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.

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

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:

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:

With increase in pressure ratio in Brayton cycle the net work output

For the same compression ratio and same heat supplied in Otto, Diesel and Dual cycles:
(A) Otto cycle has maximum efficiency.
(B) Diesel cycle has minimum heat rejected.
(C) Dual cycle has maximum heat rejected.
(D) Diesel cycle has maximum heat rejected.
Choose the correct answer from the options given below.

In a simple saturated Vapour compression refrigeration cycle, the enthalpy at various state points are: 10 kJ/kg, 45 kJ/kg and 25 kJ/kg. The mass flow rate of refrigerant is 2 kg/s:

1. The power consumption of compressor is 40 kJ/kg
2. The refrigeration capacity is 70 kW
3. The COP is 1.75
4. Heat rejected in condenser is 110 kW

Choose the correct answer from the options given below.

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.

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

The shape factor of a hemispherical body placed on a flat surface with respect to itself is

Given below are two statements:
Statement (I): The heat transfer coefficient for air in free convection varies between 5 to 30 W/m²·K.
Statement (II): The heat transfer coefficient of steam during condensation lies between 5000 to 110000 W/m²·K.
In light of the above statements, choose the most appropriate answer from the options given below.

A thermo flask is

2 kg of air is contained in a closed system at a pressure of 2 bar and 0.5 m³. It undergoes an isobaric expansion till the final volume becomes 0.6 m³. The work transfer (in kJ) during the process is:

Given below are two statements, one is labelled as Assertion (A) and the other one labelled as Reason (R):
Assertion (A): The Clausius statement of second law of thermodynamics states that it is impossible to transfer heat from a body at low temperature to a body at high temperature without the aid of external work.
Reason (R): Heat always flows from low temperature to high temperature.
In light of the above statements, choose the correct answer from the options given below:

A system at 500 K receives 7200 kJ/min of heat from a source at 1000 K The ambient temperature is 300 K The system and source temperature remain constant during heat transfer The decrease in available energy due to heat transfer through finite temperature difference is

Lumped Heat capacity analysis can be applied to a system when

Given below are two statements:
Statement (A): The flow in a pipe is turbulent when the Reynolds’ Number is more than 4000.
Statement (R): The flow in a pipe is turbulent at entry and slowly changes to laminar along the length of the pipe.
In light of the above statements, choose the correct answer from the options given below:

Consider the following statements about the flow in a convergent-divergent nozzle operating under design conditions:

1. In the divergent section, pressure is higher than the pressure in the convergent section.
2. The pressure at the throat is equal to critical pressure.
3. The pressure in the convergent section reduces.
4. The flow is subsonic in the convergent section and supersonic in the divergent section.

Choose the correct answer from the options given below.

Given below are two statements one is labelled as Assertion A and the other one labelled as Reason R

The vacuum in a closed container is 50 mm of Hg The absolute pressure in the container is