Basic Mechanical Engg. - May 2012

First Year Engineering (Set B) (Semester 1)

TOTAL MARKS: 100
TOTAL TIME: 3 HOURS (1) Question 1 is compulsory.
(2) Attempt any four from the remaining questions.
(3) Assume data wherever required.
(4) Figures to the right indicate full marks.

Answer any one question from Q1 & Q2

1 (a) Define the following mechanical properties of engineering material:
(i) Ductility
(ii) Hardness
(iii) Toughness
(iv) Machinability(7 marks) 1 (b) Discuss the stress-strain curve curve for a ductile material.(7 marks) 10 (a) A reversible heat engine delivers 0.6 kW power and rejects heat energy to a reservoir at 300 K at the rate of 24 kJ/min. Determine the cycle efficiency and temperature of the thermal reservoir supplying heat to the engine.(7 marks) 10 (b) Explain the working of a 4-stroke petrol engine.(7 marks) 2 (a) What is Alloy Steel? Name two types of alloy steel giving their composition and uses.(7 marks) 2 (b) Define hardness and explain the testing procedure for determine hardness of engineering material.(7 marks)

Answer any one question from Q3 & Q4

3 (b) Explain the construction and uses of the following measuring instruments:
(i) Dial guage
(ii) Micrometer(14 marks) 4 (a) Describe the measurement of flow rate of a fluid flowing through a circular pipe.(7 marks) 4 (b) Name and explain five operations which can be performed on a lathe machine.(7 marks)

Answer any one question from Q5 & Q6

5 (a) State Newton's law of viscosity. What is the effect of temperature on viscosity of water and gas?(7 marks) 5 (b) What is fluid coupling? Explain its working principle.(7 marks) 6 (a) Differentiate between absolute pressure and guage pressure, how can we measure pressure exerted by fluid?(7 marks) 6 (b) Differentiate between the following:
(i) Laminar and turbulent flow
(ii) Turbine and compressor(7 marks) 6 (b) What are the different methods of speed control in D.C. motor? Discuss in details.(7 marks)

Answer any one question from Q7 & Q8

7 (a) State and explain First Law of Thermodynamics.(7 marks) 7 (b) Explain the working of a simple vapour compression refrigeration cycle.(7 marks) 8 (a) Define the following terms:
(i) Sensible heat of water
(ii) Latent heat of steam
(iii) Dryness fraction of steam
(iv) Saturation temperature of steam(7 marks) 8 (b) Explain the working of a water tube boiler with me help of a neat sketch.(7 marks)

Answer any one question from Q9 & Q10

9 (a) Explain the working of a double acting steam engine with the help of a neat diagram.(7 marks) 9 (b) Differentiate between petrol and diesel engine.(7 marks)