**BE (2 ^{nd} Semester)**

**Examination May-2008**

** Basic Mechanical Engineering**

**UNIT- I**

1. (a) Define work and heat.

(b) Show that work is a path function.

(c) A piston and cylinder machine contains a fluid system which passes a complete cycle of four processes. During a cycle, the sum of all heat fers is 170 kJ. The system, completes 100 cycles per min. Complete following table.

Process Q (kJ/min) W (kJ/min) (kJ/min)

a-b 0 2,170 ̶

b-c 21,000 0 ̶

c-d -2,100 ̶ 36,600

d-a ̶ ̶ ̶

**UNIT- II**

2. (a) Define entropy.

(b)Show that entropy is a point function.

(c) Show that =* n _{otto}= 1- 1/r_{ k}*

^{r-1}

**UNIT- III**

3. (a) What is Dryness fraction ?

(b) A vessel of volume 0.04 m^{3} contains a mixture of saturated water and rated steam at a temperature of 250⁰C. The mass of the liquid present is Find the pressure, the mass, the specific volume, the enthalpy, the and internal energy.

(c) What is Blow-of-cock ? Describe it with neat sketch.

**UNIT- IV**

4. (a) Define Welding.

(b) What is oxy acetylene gas welding? Describe different types of oxy- acetylene welding flaming.

(c) What are the classifications of Lathe? Describe engine lathe**.**

** ****UNIT- V**

5. (a) Define Stress and Strain.

(b) Show stress and strain diagram for ductile and brittle material**.**

(c)Show that:

σ/K= 3σ/E[1-2/m]

where K is Bulk modulus, E is Young’s modulus of elasticity is 1/m Poisson’s ratio.