List of top Mechanical Engineering Questions

When a ball mill rotates at a speed higher than the critical speed, what happens to its efficiency?
Which mechanical drive is specifically used to impart a reciprocating or oscillatory motion to another body in contact?
What is the stress developed when a steel rod of radius \(10 \, \text{mm}\) is stretched by a \(100 \, \text{kN}\) force?
A ball is thrown vertically upward with a velocity of \(5 \, \text{m/s}\); if it takes 10 sec for the upward journey, how long does the downward journey take?
Which translatory joint in a robot configuration is known as a sliding joint?
What is the natural frequency of a free vibration system defined by the equation \( \ddot{X} + 36\pi^2 X = 0 \)?
The polar section modulus for a circular shaft of diameter \(d\) is given by which formula?
For a DC power source for arc welding with characteristics \(3V + I = 240\), what voltage \(V\) yields maximum power?
Forces whose line of action passes through a common point are known as what?
Which of the following is a coarse crusher used in mechanical operations?
The resistance to fatigue of a material is measured by
A principal plane is a plane of
In which one of the following materials the heat energy propagation is minimum due to conduction heat transfer?
A Newtonian fluid is defined as the fluid which
Which thermodynamics law predicts correctly the degree of completion of a chemical reaction?
At a point on the beam where shear force changes signs, the bending moment at that point is
Gas contained in a closed system consisting of a piston-cylinder arrangement is expanded. Work done by the gas during expansion is 50 kJ. The decrease in internal energy of the gas during expansion is 30 kJ. The heat transfer during the process is equal to:
A refrigerating machine working on a reversed Carnot cycle takes out 2 kW of heat from the system while working between temperature limits of 300K and 200K. The coefficient of performance and power consumed by the cycle will be respectively:
An aeroplane is flying at a height of 15 km, where the temperature is -50°C. Assuming \( k = 1.4 \) and \( R = 287 \, \text{J/K . kg} \), the approximate speed of the plane corresponding to \( M = 2.0 \) will be?
The latent heat of vaporization at the critical point is
After expansion from a gas turbine, the hot exhaust gases are used to heat the compressed air from a compressor with the help of a cross-flow compact heat exchanger of 0.8 effectiveness. What is the number of transfer units of the heat exchanger?
The polar section modulus for a circular shaft of diameter "d" is:
The following conditions must be satisfied for a perfect truss (m = number of members, j = number of joints):
In a psychrometric chart, what does a vertical downward line represent?
Match List-I with List-II
List-IList-II
(A) Work done in a polytropic process(IV) \( \frac{p_1 V_1 - p_2 V_2}{n - 1} \)
(B) Work done in a steady flow process(I) \( - \int v \, dp \)
(C) Heat transfer in a reversible adiabatic process(II) Zero
(D) Work done in an isentropic process(III) \( \frac{p_1 V_1 - p_2 V_2}{\gamma - 1} \)
Choose the correct answer from the options given below: