Basic Mechanical Engg. - Dec 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) Draw the stress-strain curve for a ductile metal and point out its salient features.(7 marks) 1 (b) Explain the following reactions in relation to iron-carbon equilibrium diagram.
(i) Eutectic reaction
(ii) Eutectoid reaction
(iii) Peritectic reaction(7 marks) 10 (a) With the help of theoretical P-V diagram explain working of single acting steam engine.(7 marks) 10 (b) Differentiate between SI and CI engines.(7 marks) 2 (a) Give the broad classification of engineering materials.(7 marks) 2 (b) Define the following mechanical properties of engineering material:
(i) Hardness
(ii) Toughness
(iii) Fatigue(7 marks)

Answer any one question from Q3 & Q4

3 (a) Explain the construction and uses of a combination set.(7 marks) 3 (b) Discuss the different source of error's in the act of taking measurement.(7 marks) 4 (a) Sketch a micrometer and explain its working.(7 marks) 4 (b) Explain the construction and working principle of a lathe machine with neat sketch.(7 marks) 4 (b) Derive the condition for maximum efficiency of a transformer.(7 marks)

Answer any one question from Q5 & Q6

5 (a) Establish the Bernoulli's theorem from the Euler equation of motion through a stream tube.(7 marks) 5 (b) Enumerate important characteristics of
(i) Limar flow
(ii) Turbulent flow(7 marks) 6 (a) Explain working principle of fluid coupling.(7 marks) 6 (b) A pipe 300 meters long has a slope of 1 in 100 and tapers from 1 m diameter at the high end to 0.5m at the low end. Quantity of water flowing is 5400 litres per minute. If the pressure at the high end is 70 Kpa, find the pressure at the low end.(7 marks)

Answer any one question from Q7 & Q8

7 (a) Explain with neat sketch vapour compression refrigeration system also draw P-V and T-S diagrams.(7 marks) 7 (b) Find enthalpy of stream at 10 bar in following conditions.
(i) Dry and saturated
(ii) Wet having dryness fraction 0.95
(iii) Superheated to a degree of superheat=50°C.(7 marks) 8 (a) Give classification of boilers on different basis.(7 marks) 8 (b) A coal fired boiler plant consumes 400kg of coal per hour. The boiler evaporates 3200kg of water at 44.5°C into superheated steam at a pressure of 12 bar and 274.5°C. If the calorific value of fuel is 32.760 kJ/kg of Coal, determine:
(i) Equivalent evaporation
(ii) Thermal efficiency of boiler.(7 marks)

Answer any one question from Q9 & Q10

9 (a) With the help of theoretical P-V diagram explain working of four stroke petrol engine.(7 marks) 9 (b) Explain carnot cycle and find expression for efficiency.(7 marks)