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Awadhesh Pratap Singh University 2007 M.Sc Microbiology physics - Question Paper

Thursday, 17 January 2013 09:50Web

1. a) State the conditions under which 2 shafts connected

together by a double Hooke’s joint shall have the identical

angular velocities. (3)

b) describe coriolis component of acceleration. Indicate its

magnitude and direction. (3)

c) What conditions must be satisfied by 2 mass system to

be dynamically equivalent to the rigid body? (3)

d) discuss the terms Friction circle and Friction axis. (3)

flat belts and (ii) chains for the transmission of power. (3)

2. a) What do you mean by constrained motion? discuss various

kinds of constrained motions with examples and neat

sketches. (7)

b) discuss inversions of a 4 bar chain with neat sketches.

(8)

3. In the mechanism shown in Fig. 1, OA is fixed, CD = 200

mm, OA = 60 mm, AC = 50 mm and OB (crank) = 150

mm, ÐOAD = 900. Determine the velocity and acceleration

of ‘D’ for counter clock wise rotation of OB at 80 rpm.

(15)

II Year B.E./B.Tech Degree exam

THEORY OF MACHINES - I

Mechanical Engineering

Time : 3 hours Maximum : 75 Marks

14

A

D

C

B

O

45º

4. a) Hook’s joint connects 2 shafts intersecting at 1500. The

driving shaft rotates at 120 rpm. The driven shaft operates

against a steady torque of 150 Nm and carries a flywheel of

mass 45 Kg and radius of gyration 15 cm. What is the

maximum torque which must be exerted by driving shaft?

(7)

b) elaborate various kinds of steering gear mechanisms ? Show

that Davis steering gear mechanism provides accurate

steering. (8)

5. a) The subsequent data relate to a connecting rod of a reciprocating

engine:

Weight = 550 N, Distance ranging from bearing centres = 85

cm, Diameter of small end bearing = 7.5 cm, Diameter of

big end bearing = 10 cm, Time of oscillation when the
connecting rod is suspended from small end = 1.83 sec,

Time of oscillation when the connecting rod is suspended

from big end = 1.68 sec.

Determine (a) the radius of gyration of the rod about an axis

through the centre of gravity perpendicular to the plane of

oscillation; (b) the moment of inertia of the rod about the

identical axis and (c) the dynamically equivalent system for the

connecting rod. Constituted of 2 masses, 1 of which is

situated at the small end centre. (15)

Fig . 1

15
6. a) A certain machine tool does work intermittently. The machine

is fitted with a flywheel of mass 200 Kg and radius of gyration

of 0.4 m. It runs at a speed of 400 rpm ranging from the

operations. The machine is driven continuously by a motor

and every operation takes eight seconds. When the machine is

doing its work, the speed drops from 400 to 250 rpm. obtain
(i) Minimum power of the motor, where there are 5

operations performed per minute and (ii) Energy expanded

in performing every operation. (15)

7. a) Deduce and expression for the friction moment of a conical

thrust bearing and state what assumptions are made. (7)

b) compute the power absorbed in overcoming friction and

number of collars needed for the thrust bearing whose collars

have 20cm external radius and 15cm internal raidus.

Coefficient of friction is 0.03. Total axial load is 30 KN.

Intensity of pressure is 0.35 N/mm2, speed of shaft is 420
rpm. (8)

8. a) A governor of the Hartnell kind has equal balls of mass 3

Kg, set initially at a radius of 200 mm. The arms of the bell

crank lever are 100 mm vertically and 150 mm horizontally.
obtain (i) The initial compressive force on the spring, if the

speed for an initial ball radius of 200 mm is 240 rpm and (ii)

The stiffness of the spring needed to permit a sleeve

movement of four mm on fluctuation of 7½ percent in the engine

speed. (8)

b) define the construction and operation of a rope brake

absorption dynamometer. (7)