Mechanical Engineering Optional – Other Questions Outside the Present Syllabus (1995–2026)

These 18 questions from UPSC Mechanical Engineering Optional papers (1995–2026) fall outside the present syllabus of their paper – mostly from papers set on the older syllabus. We keep them here for completeness.

Each question ends with a code such as [2024/15m/3b] – the year, the marks, the word limit (where UPSC set one) and the question number in the paper.

Paper I

18 questions

1. (i) With a neat sketch briefly explain organization of digital computer. (ii) Write down the general structure of a logical IF statement in modern FORTRAN language. (iii) Differentiate between a function sub programme and sub-routine. [2007/20m/5d]

2. Write a “C” program to calculate the factorial of a positive integer quantity by incorporating user defined function for calculating factorial in main program. [2006/20m/8c]

3. Write a flow chart to solve the quadratic equation $a{x}^2+bx+c=0$. Write also the corresponding C program. [2005/20m/8c]

4. Write a flow chart for choosing the largest of three distinct numbers X, Y and Z. [2004/30m/8b]

5. (i) Bevery Company, a weighing machine manufacturer essentially manufactures a mechanical weighing machine and another deluxe version which is a digital weighing machine. The company gives 7% commission on sales of the ordinary mechanical type and 8% commission on sales of the deluxe digital version. However, all such commissions are available, provided there is a base level sale of at least Rs. 10,000 of ordinary variety and Rs. 15,000 of deluxe variety. To motivate the sales engineers, for a sales exceeding Rs. 20,000 and Rs. 25,000 for the ordinary and deluxe variety respectively, there is a 1% increase in the commission levels for both varieties. Draw a flow chart to enable writing a computer programme for the above. (ii) Write a computer programme for the above situation. [2002/20m/5d]

6. (i) List the primary hardware components of a personal computer. (ii) List some of the options for each of the above components. (iii) What do you understand from the following terms? (a) RAM (b) ROM (c) 5 GB (d) 860 MHz (e) 57.6 KBPS. [2001/20m/5c]

7. Write a FORTRAN programme to accept data of heights of up to 100 students of a college. The programme should be able to calculate the main variance, and standard deviation of heights and print (i) the number of students (ii) the serial number and heights of individual students (iii) the mean, variance and standard deviation of heights. [2001/20m/5d]

8. A 150 mm diameter shaft supporting a load of 10 kN has a speed of 1500 rpm. The shaft runs in a bearing whose length is 1.5 times the shaft diameter. If the diametral clearance of the bearing is 0.15 mm and the absolute viscosity of the oil at the operating temperature is 11 centipoises find the power wasted in friction. [2000/30m/3b]

9. A ball at the end of a very long pendulum can be assumed to move linearly between two metallic plates at a fixed distance apart. The inner distance between the plates is slightly more than the diameter of the pendulum bob which is spherical leaving clearance on the left or on the right. If the plates move in simple harmonic motion, the amplitude being very small, the bob may touch the left or the right side plate or it may not touch any, at any instant. If the bob touches the left plate, equation A is governed while if it touches the right plate, equation B is governed. If there is no contact by the bob on any of the plates, then equation C is governed. Write a flow chart in FORTRAN for the motion of the bob. [2000/20m/5d]

10. Draw the flow chart and write a computer programme in Fortran for computing standard deviation $\sigma$ of a given set of 100 numbers $x_1,x_2,\dots ,x_{100}$, where $\sigma =\sqrt{\frac{1}{N}{\sum }_{i=1}^N{(x_i-\overline{x})}^2}$ where x is an individual number of a group $\overline{x}$ is the arithmetic mean of the group of numbers and N is the size of the group of numbers. [1999/20m/1c]

11. Explain the mechanism of hydrodynamic and boundary lubrications. State with justification the important properties of lubricant in each case. [1998/20m/200w/1a]

12. Write an interactive file-oriented C programme that will maintain the list of names, addresses and telephone numbers in alphabetical order (by last name). Consider the information associated with each name to be a separate record and represent each record as a structure. [1998/20m/200w/1d]

13. Write a FORTRAN programme for the amount payable (A) after n years on a principle amount (P) at a rate of interest (i%) compounded annually. The formula for calculating the amount is given below: $A=P{(1+\frac{i}{100})}^n$ [1997/20m/200w/5b]

14. What is the classical Reynold’s Equation for one dimensional fluid flow based on Hydrodynamic lubrication theory? What are the assumptions made in arriving at this equation? Explain the significance of Sommerfeld Number, Temperature Rise and Minimum Film Thickness for assessing a bearing performance. [1996/20m/200w/1d]

15. There are ‘NSTUD’ students in a class whose roll numbers are given in an array ‘NROLL’ and the marks obtained in the final examination are given in array ‘TOTAL’. Write a program, in FORTRAN, to read roll numbers and corresponding marks of all the students and arrange them in order of merit. Assume the value of ‘NSTUD’ as 40. [1996/20m/7c]

16. A tank having liquid capacitance $C_1$ is supplying liquid through a pipe of resistance $R_1$ to another tank of liquid capacitance $C_2$ which delivers this liquid through another pipe of resistance $R_2$. The steady-state outflow rates of tank 1 and that of tank 2 are $Q_1$ and $Q_2$ and heads are $H_1$ and $H_2$ respectively. The flow balance equation for tank 1 is $\Delta Q=\Delta Q_1+C_1\frac{d}{dt}\left(\Delta H_1\right)$ Similarly for tank 2 is $\Delta Q_1=\Delta Q_2+C_2\frac{d}{dt}\left(\Delta H_2\right)$ where $\Delta Q_1=(\Delta H_1-\Delta H_2)/R_1$; $\Delta Q_2=\Delta H_2/R_2$ and Δ’s show small variations of quantities. Draw the overall feedback block diagram of the system and obtain the transfer function.

[Figure: Two open tanks side by side, “Tank 1” (capacitance $C_1$) on the left and “Tank 2” (capacitance $C_2$) on the right, both containing liquid. Inflow Q enters Tank 1 from the top through a valve. A pipe at the bottom of Tank 1 carries flow $Q_1$ (labelled below the pipe) to Tank 2; a pipe at the bottom of Tank 2 discharges to the right (arrow; its label is not legible in the copy)] [1995/30m/4a]

17. Write complete program in C-language to obtain the output: Civil Services Examination. [1995/20m/200w/5c]

18. The frictional force f(x) acting on a body is expressed by the following: $f\left(x\right)=0\left|x\right|\le 0.5$ $=2x^2\mathrm{\text{for}}x>0.5$ This function is required to be used in the following equation: $g=\left(\frac{mv}{t}\right)-f\left(v^2\right)+at$ Write a FORTRAN programme for the stated problem. [1995/30m/8a]

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Last updated: 30 October 2026