RGPV Basic Mechanical Engineering Previous year Question Paper April 2009

RGPV Basic Mechanical Engineering

Previous year Question Paper April 2009

Note:- Attempt any five question .All questions carry equal marks.

Q.1.Discuss composition,specific properties & main applications of the following materials:20
(a) Mild steel (Low carbon steel)
              (b) High carbon steel
              (c) High speed steel               (d) Stainless steel.
Q.2 Describe the mechanical properties of materials  20
              (a) Tensile strength (tensile stress)
              (b) Hardness
              (c) Fatigue strength
              (d) Modulus of elasticity
              (e) Toughness
Q.3 Explain the following properties of any measuring instruments: 20
              (a) Hysteresis
              (b) Sensitivity
              (c) Response time
              (d) Precision and accuracy
Q.4 With the help of diagram explain various parts of a lathe machine & also enumerate various operations which can be performed on it.  20
Q.5 What is Newton’s law of viscosity?

A plate requires 2 N force per unit area or 2 N/m² to move with a velocity of 60 cm/s over a fixed plate.The distance between two plates is 0.03 mm.Determine fluid viscosity between plates.5 + 15

Q.6 Derive the Bernoulli’s equation from Euler’s equation for an ideal flow.
The water is flowing through a pipe having diameters 20 cm at inlet section 1 and 10 cm at outlet section 2. The rate of flow through pipe is 35 litres/s. The section 1 is 6 m above datum and section 2 is 4 m above datum. If pressure at section 1 is 39.24 N/cm², find the intensity of pressure at section 2. 6+14
Q.7 Explain the First Law of Thermodynamics with suitable examples. In a gas turbine the gas enters at the rate of 5 kg/s with a velcity of 50 m/s and enthalpy of 900 kJ/kg and leaves the turbine with a velocity of 150 m/s and enthalpy of 400 kJ/kg. The loss of heat from the gases to the surroundings is 25 kJ/kg. Assume for gas R = 0.285 kJ/kg-K and Cp = 1.004 kJ/kg-K and the inlet section conditions to be at 100 kPa and 27ºC. Determine the power output of the turbine and diameter of the inlet pipe 6+14
Q.8 Give the two statements of Second Law of Thermodynamics. Which is the more effective way to increase the efficiency of a Carnot engine: To increase T1 keeping T2 constant or To decrease T2 keeping T1 constant. where T1 is the source temperature and T2 is the sink temperature.20
Q.9 Show that the efficiency of the Otto cycle depends only on the compression ratio. In a SI engine working on the ideal Otto cycle,compression ratio is 5.5.The pressure and temperature at the beginning of compression are 1 bar and 27 ºC respectively. The peak pressure is 30 bar. Determine the pressure and temperatures at the salient points, the air-standard efficiency and the mean effective pressure. Assume ratio of specific heats to be 1.4 for air. 6 + 14
Q.10 What is the basic difference between an Otto cycle and a Diesel cycle? Derive the expression for the efficiency and mean effective pressure of the diesel cycle 6 + 14

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