Mechanics of Machines , Question Paper of B.Tech 4th Semester,Download Previous Years Question Paper 2

Roll No.

Total No. of Questions: 09]

B. Tech. (AE) (Sem.4th)

Mechanics of machines

Subject Code:-BTAE – 402

Paper ID –A162

Time: 3 Hrs.

INSTRUCTION TO CANDIDATES:

l) Section A is Compulsory.

 2) Attempt any Four Questions from section - B

3) Attempt any Two Questions from section - C

Section – A

   

a.     What is the function of governor?

b.     Define the terms: sensitivity, Hunting in relation of to governors.

c.      Differentiate between machine and structure.

d.     Define the term ‘degree of freedom’ for a mechanism.

e.      What to do you mean by ‘completely constrained motion’?

f.       Differentiate between turning pair and sliding pair.

g.     What is effect of creep on velocity ration of a belt drive?

h.     State the effect of centrifugal force on power transmission in belt drive.

i.       What is the need of balancing?

j.       Why is cam profile important ? explain with suitable example.

Section –B

2.     What is a quick return mechanism? Sketch and explain the functioning of any one of them.

3.     Derive an expression of the length of a belt in an open belt drive.

4.     With the help of a neat sketch, derive the equation for  the equilibrium speed of a Proell governor.

5.     How the function of a flywheel is different from that of governor? Also explain the terms ‘fluctuation of speed’ and ‘fluctuation of energy’ in context to flywheels.

6.     Four masses A,B,C and D carried by a rotating shaft at radii 200mm, 150mm, 250mm and 300mm are 200kg, 300kg,240kg and 260 kg respectively. The angles between respective masses are 45*, 75* and 135*. Find the position and magnitude of balancing mass required, if its radius of rotation is 0.2m.

Section –c

7.     Draw the profile of the cam that dries a flat reciprocating follower in the following manner:

a.     During first 120* rotation of the cam, follower moves outwards through a distance of 20mm with SHM

b.     Follower dwells for the next 30* of cam rotation.

c.      During next 120* of cam rotation, the follower moves inward with SHM

d.     Follower dwells for the next 90* of cam rotation.

Given that the minimum radius of the cam is 25mm

8.     A punching press is required to punch 40 mm diameter holes in a plate of 15 mm thickness at the rate of 30 holes per minute. It requires 6 Nm of energy per mm2 of shaded area. If the punching takes1/10 of a second and rpm if the fly wheels v varies from 160 to 140 , find out the mass of the flywheel having radius of gyration of 1m

9.     Discuss the ‘Direct and Reverse  crank’ method for balancing of radial engines by taking suitable example.