List of top Mechanical Engineering Questions

All of the following options describe the availability and unavailable energy of a system EXCEPT:
For a balanced counter flow heat exchanger where \( \dot{m}_h C_{ph} = \dot{m}_c C_{pc} \), the logarithmic mean temperature difference (LMTD) and temperature profile is:
A bullet is fired upwards at an angle of \(30^\circ\) to the horizontal from a point P on a hill, and it strikes a target which is 80 m lower than P. The initial velocity of the bullet is 100 m/s. Calculate the maximum height to which the bullet will rise above the horizontal. Assume \( g = 9.81 \) m/s\(^2\).
Air enters the compressor at 100 kPa and 25°C having the volume of 1.8 m3/kg and compressed to 5 bar isothermally. The change in internal energy during the process is
Which of the following is not a principal classification model representing the 3D geometric modelling?
For maintaining records, —––––––––– cards contain information on the (a) type of part, (b) location where the card was issued, (c) part number, and (d) number of items in the container.
Calculate the matrix product \( C = AB \), where
\[A = \begin{bmatrix} 5 & 3 & 1 \\ 4 & 6 & 2 \\ 10 & 3 & 4 \end{bmatrix}, \quad B = \begin{bmatrix} 1 & 5 \\ 2 & 4 \\ 3 & 2 \end{bmatrix}\]
A 6×19 wire rope with fiber core and tensile designation of 1570 is used to raise the load of 20 kN as shown in the below figure. The nominal diameter of the wire rope is 12 mm, and the sheave has 500 mm pitch diameter. Determine the expected life of the rope in years assuming 500 bends per week. 
wire rope with fiber core and tensile designation
The following equation is equal to the value of \[ \left( \frac{\partial T}{\partial V} \right)_P \left( \frac{\partial V}{\partial T} \right)_P \left( \frac{\partial P}{\partial V} \right)_T = ? \]
The application for which a point to point numerical control system can be employed is a
The gearing of a machine tool is shown in the below figure. The motor shaft is connected to gear A and rotates at 975 rpm. The gear wheels B, C, D, and E are fixed to parallel shafts rotating together. The final gear F is fixed on the output shaft. What is the speed of gear F? The number of teeth on each gear are as follows: \( A=20 \), \( B=50 \), \( C=25 \), \( D=75 \), \( E=26 \), and \( F=65 \). 
gearing of a machine tool
Cracks appear in weld and base metal when the localized stresses exceed the ——––––––––– strength of a metal.
Consider the indicator diagram for the heat engine as shown in the following figure. If the heat rejected by the engine to a heat sink is 1250 kJ/kg, the thermal efficiency (by considering one decimal place) of the engine is:
heat engine
Which of the following is an incorrect operation in relation to the finishing processes employed for gear teeth?
A riveting machine is driven by a constant torque 3 kW motor. The moving parts including the flywheel are equivalent to 150 kg at 0.6 m radius. One riveting operation takes 1 second and absorbs 10000 N-m of energy. The speed of the flywheel is 300 r.p.m. before riveting. Find the speed immediately after riveting. How many rivets can be closed per minute?
For the same maximum pressure and same heat input in the air standard cycles, which of the following option is CORRECT?
A pool is filled with water and the pool has a maximum depth of 100 m. If the atmospheric pressure is 101 kPa, the absolute pressure at 100 m depth of the pool is:
A slab of 250 mm thick is made up of material ‘X’ and its thermal conductivity is 500 W/m·K. One of the surface is kept at 100°C and another surface is maintained at 25°C. The net heat flux across the surface is:
The following are the selection characteristics considered while choosing a material for brake lining. Identify the incorrect characteristic.
If \( k \) is the average height of irregularities and \( \delta \) is the thickness of the laminar sublayer, then the boundary is known to be hydrodynamically rough when:
A slender pin-ended aluminium column 1.8 m long and of circular cross-section is to have an outside diameter of 50 mm. Calculate the necessary internal diameter to prevent failure by buckling if the actual load applied is 13.6 kN and the critical load applied is twice the actual load. Take \( E \) for aluminium as \( 70 \) GN/m\(^2\).
In a Vapour Compression Refrigeration System (VCRS), if throttle valve is replaced with expansion cylinder, the COP will
In a hydraulic system, the point of intersection of the line of action of the resultant hydrostatic force and the corresponding surface is known as:
Currently, eighty-five percent of all neck injuries are caused by rear-end car collisions. To alleviate this problem, an automobile seat restraint has been developed that provides additional pressure contact with the cranium. During dynamic tests, the distribution of load on the cranium has been plotted and shown to be parabolic. Determine the equivalent resultant force and its location, measured from point A. 
neck injuries
Consider the h-s diagram for the Rankine Cycle as shown in Figure. According to the h-s diagram, which of the following steady flow devices is responsible for process 3-4? 
Rankine Cycle