A 1100MET301122101 Pages: 3
Reg No.:_______________ Name:__________________________
APJ ABDUL KALAM TECHNOLOGICAL UNIVERSITY
Fifth Semester B.Tech Degree Examination December 2021 (2019 scheme)
Course Code: MET301
Course Name: MECHANICS OF MACHINERY
Max. Marks: 100 Duration: 3 Hours
PART A
(Answer all questions; each question carries 3 marks) Marks
1 What is the difference between a machine and a mechanism? Give examples 3
2 What is kinematic inversion? 3
3 How the direction of coriolis acceleration is obtained? 3
4 Obtain an expression for maximum velocity when a cam follower motion is 3
simple harmonic
5 What is interference in gears? 3
6 What are precision points in kinematic synthesis? 3
7 What are the conditions for static equilibrium of a body? 3
8 How does gyroscope helps in the guidance of ships? 3
9 What is the difference between static balancing and dynamic balancing? 3
10 What is partial balancing in reciprocating engines? 3
PART B
(Answer one full question from each module, each question carries 14 marks)
Module -1
11 a) Sketch and explain inversions of 4R four bar chain 10
b) What are coupler curves? 4
12 Given a four bar mechanism ABCD with following dimensions. Find the 14
velocity of joint C and angular velocities of link CD and BC if the angular
velocity of link AB is 10 rad/sec in clockwise direction. Dimensions of various
links are AB = 30cm, BC=CD=35cm, AD(fixed) = 60cm, angle BAD = 60o
.Use graphical method
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1100MET301122101
Module -2
13 a) In a slider crank mechanism, crank length is 200mm, connecting rod length is 10
600mm, angular velocity of crank is 50 rad/sec clockwise and angular
acceleration of crank is 800 rad/sec2 (clockwise), Crank angle when turned
o
from inner dead centre is 120 . Find the angular velocity and angular
acceleration of the connecting rod.
b) Obtain an expression for Coriolis acceleration? 4
14 The exhaust valve of a diesel engine has a lift of 3cm. It is operated by a cam to 14
give equal uniform acceleration and retardation during rise and return. The rise
is 900 of cam rotation followed by dwell during 150 and return during 1200, then
dwell during remaining period. Line of stroke of 2cm diameter roller follower
is passes through the axis of the cam. Base circle diameter is 6 cm. Draw the
displacement diagram and the profile of cam.
Module -3
15 a) Explain and illustrate law of gearing. 6
o
b) A pair of gears having 40 and 30 teeth are of 25 involute form. 8
The addendum length is 5mm and module is 2.5 mm.
If the smaller wheel is driver and rotates at 1500 rpm.
Find the sliding velocity
1) at the point of engagement,
2) at the point of disengagement, and
3) at pitch point.
16 a) Design a four-bar mechanism which can co-ordinate the input and output 9
angles as given.
Input crank angle 40o, 60o, 90o : Output crank angle 10o, 40o, 70o
b) Explain overlay method of synthesis 5
Module -4
17 Find the torque T and its direction of slider crank mechanism shown in the 14
figure below to bring the system in equilibrium, given the forces acting on the
slider, F = 5000N and a force of magnitude 1000N is applied on the connecting
rod as shown in figure, the crank angle = 40o. Length of the crank = 250mm,
connecting rod = 750mm, AC =250mm
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1100MET301122101
18 a) Explain different planes of gyroscope. 4
b) An aeroplane flying at 240 km/hr turns towards left and complete a quarter 10
circle of 60 m radius. The mass of the rotary engine and the propeller of the
plane amounts to 450 kg with a radius of gyration of 320 mm. the engine speed
is 2000 rpm, clockwise when viewed from the rear. Determine the gyroscopic
couple on the aircraft and state its effects. In what way is the effect changed
when (i) the aeroplane turns towards right and (ii) the engine rotates clockwise
when viewed from the front (nose end) and aeroplane turns (a) left (b) right?
Module -5
19 a) What are the conditions for static balancing and dynamic balancing? 4
b) There are four planes A, B, C and D. The masses attached and radius of 10
rotation respectively are given as follows. m1 = 20kg, m2 = 30kg, m3 = 24kg, m4
= 26kg, r1 = 9cm, r2 = 7cm, r3 = 10cm, r4 = 12cm. The plane A is 12cm to the
left of reference plane L. Planes B, C and D are 5cm, 30cm and 60cm
respectively to the right of plane L. The distance between the reference planes
L and M being 50cm. m2 is at an angle of 45O from m1, m3 is at an angle of 75O
from m2 and m4 is at 135O from m3. Find the magnitude and position of the
balance mass required in planes L and M at a radius of 24 cm.
20 a) Explain the balancing of V-engines. 7
b) Explain the balancing of a four cylinder in-line engine. 7
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