UPSC Mechanical Engineering 2026

(a) A uniform beam has a mass of 50 kg per metre length. Compute the reactions at the support O. The force loads shown lie in a vertical plane. (10 marks) (b) The fixed-ended bar…

(a) What is heat treatment ? What is its purpose ? Explain different heat treatment processes with the help of common microstructural phases of steel on an Iron-Carbon equilibrium…

(a) (i) The acceleration of a particle along a straight line is defined by a = (2t – 9) m/s², where t is in seconds. At t = 0, s = 1 m and v = 10 m/s. When t = 9 s, determine : (I…

(a) A simple beam is loaded as shown in the figure. Using the double-integration method, determine the following : (i) The equation of the elastic curve (ii) The slope at the end…

(a) A cylindrical workpiece of 60 mm diameter is turned down to 50 mm over a length of 120 mm on a CNC lathe with cutting speed of 120 m/min and feed of 0·3 mm/rev. Find the machi…

(a) A strip of width 250 mm is reduced from 30 mm to 20 mm thickness in a rolling mill of roll radius 400 mm. Considering coefficient of friction 0·25 and average flow stress 300…

(a) (i) In an orthogonal cutting operation, the following data are obtained : Cutting force F_c = 1500 N Thrust force F_t = 900 N Rake angle α = 10° Chip thickness ratio r = 0·4 D…

(a) A shaft of nominal size 60 mm is to be fitted into a hole. The tolerances are : Hole tolerance – 0·030 mm Shaft tolerance – 0·020 mm Minimum clearance required – 0·010 mm Dete…

(a) A piston-cylinder contains 2 kg of argon at T₁ = 300 K and V₁ = 1 m³ (state 1). Argon is heated by an electric heater of 10 A, 220 volts for 10 seconds at constant volume; dur…

(a) (i) During a heat transfer process, the entropy change of incompressible substances, such as water, can be determined from ΔS = mC_avg ln (T₂/T₁). Show that for thermal energy…

(a) Steam at 40 °C is condensed in a power plant using cooling water available at 12 °C. The flow rate of steam is 0·15 kg/s. The cooling water is circulated through a bank of 6 m…

(a) (i) What does the NTU of a heat exchanger represent? Is a heat exchanger with a very large NTU necessarily a good one? (10 marks) (ii) Consider an oil-to-oil double-pipe heat…

(a) The air-fuel ratio of an SI engine varies under different operating conditions. Write the air-fuel ratio requirement for an engine under the following conditions with reasons…

(a) In an Otto cycle, the pressure and temperature at the beginning of compression are 1 bar and 47 °C, respectively. Calculate the theoretical thermal efficiency of this cycle, i…

(a) In a cogeneration plant, the net power output is 6 MW and the heating load is 1·5 MW. Steam is generated at 40 bar and 500 °C, and is expanded isentropically through a turbine…

(a) An air-conditioned space is maintained at 25 °C DBT and 50% RH. The outside conditions are 40 °C DBT and 27 °C WBT. The space has a sensible heat gain of 24·5 kW. Conditioned…