Download GTU (Gujarat Technological University) BE/BTech (Bachelor of Engineering / Bachelor of Technology) 2019 Winter 5th Sem Old 151902 Theory Of Machines Previous Question Paper
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ?V (Old) EXAMINATION ? WINTER 2019
Subject Code: 151902 Date: 29/11/2019
Subject Name: Theory Of Machines
Time: 10:30 AM TO 01:00 PM Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
Q.1 (a) Define (i) Hunting (ii) Sensitiveness (iii) Sleeve lift and (iv) Isochronisms for
governor.
07
(b) What is the function of dynamometer? Classify the dynamometers. Explain with
neat sketch any one dynamometer.
07
Q.2 (a) What is meant by a self locking and a self energized brake? 07
(b) The arms of a porter governor are each 25 cm long and pivoted on the governor
axis. Mass of each ball is 5 kg and mass of the central sleeve is 30 kg. The radius
of rotation of the balls is 15 cm when the sleeve begins to rise and reaches a value
of 20 cm for maximum speed. Determine the range of the governor.
07
OR
(b) Give classification of governors. Prove that, for Watt governor, height of the
governor h = 895/ N
2
. Where N is speed of rotation of sleeve.
07
Q.3 (a) Describe the construction and operation of a rope brake dynamometer. 07
(b) A differential band brake shown in Figure, has an angle of contact of 225
o
. The
band has a lining whose coefficient of friction is 0.3 and the drum diameter is
400mm. The brake is to sustain a torque of 375 Nm. Find (i) the necessary force
for the clockwise and counter-clockwise rotation of the drum and (ii) the value
of OA for the brake to be self-locking, when the drum rotates clockwise.
07
OR
Q.3 (a) List various terms used for Ship. Explain the gyroscopic effect of rotor of ship in
case of rolling, pitching and steering.
07
(b) The moment of inertia of an aero plane propeller is 20 kg.m
2
and the speed of
rotation is 1250 rpm clockwise when viewed from the front. The speed of the
flight is 200 km/hr. Calculate the gyroscopic reaction of the propeller on the aero
plane when it makes a left hand turn on a path of 150 m radius.
07
Q.4 (a) Explain the turning moment diagram for 4 cylinder four stroke cycle internal
combustion engine.
07
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1
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ?V (Old) EXAMINATION ? WINTER 2019
Subject Code: 151902 Date: 29/11/2019
Subject Name: Theory Of Machines
Time: 10:30 AM TO 01:00 PM Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
Q.1 (a) Define (i) Hunting (ii) Sensitiveness (iii) Sleeve lift and (iv) Isochronisms for
governor.
07
(b) What is the function of dynamometer? Classify the dynamometers. Explain with
neat sketch any one dynamometer.
07
Q.2 (a) What is meant by a self locking and a self energized brake? 07
(b) The arms of a porter governor are each 25 cm long and pivoted on the governor
axis. Mass of each ball is 5 kg and mass of the central sleeve is 30 kg. The radius
of rotation of the balls is 15 cm when the sleeve begins to rise and reaches a value
of 20 cm for maximum speed. Determine the range of the governor.
07
OR
(b) Give classification of governors. Prove that, for Watt governor, height of the
governor h = 895/ N
2
. Where N is speed of rotation of sleeve.
07
Q.3 (a) Describe the construction and operation of a rope brake dynamometer. 07
(b) A differential band brake shown in Figure, has an angle of contact of 225
o
. The
band has a lining whose coefficient of friction is 0.3 and the drum diameter is
400mm. The brake is to sustain a torque of 375 Nm. Find (i) the necessary force
for the clockwise and counter-clockwise rotation of the drum and (ii) the value
of OA for the brake to be self-locking, when the drum rotates clockwise.
07
OR
Q.3 (a) List various terms used for Ship. Explain the gyroscopic effect of rotor of ship in
case of rolling, pitching and steering.
07
(b) The moment of inertia of an aero plane propeller is 20 kg.m
2
and the speed of
rotation is 1250 rpm clockwise when viewed from the front. The speed of the
flight is 200 km/hr. Calculate the gyroscopic reaction of the propeller on the aero
plane when it makes a left hand turn on a path of 150 m radius.
07
Q.4 (a) Explain the turning moment diagram for 4 cylinder four stroke cycle internal
combustion engine.
07
2
(b) A flywheel fitted to a punching press runs at 250 rpm and has radius of gyration
is 1m. The press punches 700 holes per hour. The energy required for each
punching operation is 20KN.m and 2 second for each operation, determine the
power of the motor and mass of the flywheel if speed of the flywheel is not fall
below 220 rpm.
07
OR
Q.4 (a) What are the differences between governor and flywheel? Specify their use in
particular application.
07
(b) Explain the term (1) Turning moment diagram, (2) Coefficient of fluctuation of
speed and (3) Coefficient of fluctuation of energy.
07
Q.5 (a) Draw and explain Klein?s construction for determining the velocity and
acceleration of the piston in slider crank mechanism.
07
(b) A vertical IC engine has a cylinder bore of 150 mm and stroke of 200 mm. The
connecting road is 350 mm long. The mass of the reciprocating parts is 1.6 kg.
During the expansion stroke with crank angle 30
o
from top dead centre, the gas
pressure is 750 kN/m
2
. Determine the piston effort when engine runs at 1800 rpm.
07
OR
Q.5 (a) Describe the procedure to design a four-bar mechanism by relative pole method
when three positions of the input link (?1, ?2, ?3) and the output link (?1, ?2, ?3)
are known.
07
(b) Synthesise a 4-bar linkage using Freudenstein?s equation to generate the function
y = x
1.5
for the interval 1 ? x ? 4. The input crank is to start from 30
o
and have a
range of 90
o
. The output follower is to start from 0
o
and have range of 90
o
. Take
three accuracy points. Assume length of the fixed link to be 50 mm.
07
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This post was last modified on 20 February 2020