UPSC Mechanical Engineering 2025

(a) A gripper is shown in the figure. A horizontal force F = 50 N is applied to the handle of the lever at E. The mean diameter of the single square threaded screw at C and E is 2…

(a) (i) A cylinder C weighing 1000 N is supported by two cylinders A and B weighing 500 N each as shown in the figure. Calculate the contact forces at P, Q and R. (10 marks) (ii)…

(a) (i) The recoil mechanism of a gun consists of a critically damped spring-damper system. The maximum permissible recoil distance of the gun is specified as 0·5 m. If the initia…

(a) A car is moving in a straight line with a velocity of v = (0·6t² + 2t) m/s for a short duration, where t is in seconds. Take initial time t = 0, s = 0. Find : (i) distance tra…

(a) A low carbon steel stock of thickness 25 mm is to be rolled in two stages. In the first stage, the reduction is to be from 25 mm to 15 mm and in the second stage from 15 mm to…

(a) (i) If the power source characteristic in a Metal Inert Arc welding process is V_P = 38 - I/60, and the arc characteristic is V_a = 3L_a + 27, where V_P and V_a is voltage, I…

(a) HSS cutting tool with 9° rake angle, the following data were observed in an orthogonal machining process of medium carbon steel workpiece: Feed rate = 0·25 mm/rev Cutting spee…

(a) What are the various computer languages used for NC machines? Explain the merits and limitations of each language. (10 marks) (b) A small manufacturing unit produces bolts and…

(a) A lump of ice with a mass of 1·5 kg at an initial temperature of 260 K melts at the pressure of 1 bar as a result of heat transfer from the environment. After some time, the r…

(a) (i) A reversible power cycle engine is used to drive a reversible heat pump. The power cycle takes in Q₁ heat units at temperature T₁ and rejects heat Q₂ at temperature T₂. Th…

(a) A long cylindrical rod of radius 10 cm consists of a nuclear reacting material (k = 0·5 W/m-K) generating 24000 W/m³ uniformly throughout its volume. The rod is encapsulated w…

(a) A shell and tube type condenser is employed in a steam power plant to handle 35000 kg/h of dry and saturated steam at 50 °C. The cooling water enters the condenser at 15 °C an…

(a) With the help of P-θ (pressure-crank angle) diagram, compare the knock in SI and CI engines. Explain that "the factors which tend to prevent knock in SI engines in fact promot…

(a) A single-cylinder, two-stroke, high-speed diesel engine working on 'dual cycle' has a compression ratio of 15 : 1. The engine takes in atmospheric air at 1 bar and 27 °C. The…

(a) A two-stage turbine receives steam at 50 bar and 350 °C. At 1·5 bar, the high-pressure stage exhausts and 12000 kg of steam per hour is taken at this stage for process heating…

(a) The following data refers to a single-stage vapour compression refrigeration system : Refrigerant = R134a Condenser temperature = 35 °C Evaporator temperature = – 10 °C Compre…