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UNIT-I
A] Theory Question Bank
Q. No Description
1 Define the following terms :
(i) Kinematic chain
(ii) Structure
(iii) Kinematic pair
(iv)Degree of freedom in Mechanism.
2 Define inversion of a mechanism. Explain with the
help of neat sketches inversions of double slider
crank chain. Give their applications.
3 Calculate the number of degree of freedom of the
mechanism As shown
4 Explain the following terms with suitable examples :
(i) Completely constrained motion
(ii) Incompletely constrained motion
(iii) Successfully constrained motion.
5 Explain with neat sketches ‘Swinging and Rocking
Mechanisms’.
6 What is the condition for correct steering? Explain
with neat sketch Ackermann steering gear
mechanism.
7 Describe the three kinds of lower pairs, giving a
sketch of each kind, and state the types of relative
motion that each
pair permits.
8 Explain with a neat sketch ‘Geneva Mechanism’.
9 Fill in the blanks with correct alternative and
rewrite the
complete sentences :
(i) Oldham’s coupling is the inversion
of.............................. .
(a) Four bar mechanism
(b) Crank and lever mechanism
(c) Single slider crank mechanism
(d) Double slider crank mechanism
(ii) ..........................number of pairs are associated
with quaternary
joint.
(a) 1
(b) 2
(c) 3
(d) 4
(iii) A combination of kinematic pairs, joined in
such a way
that the relative motion between the links is
completely
constrained, is called a........................... (a)
Structure
(b) Mechanism
(c) Kinematic Chain
(d) Inversion
10 What is meant by a ‘steering gear mechanism’? Why
is it necessary? Why are steering gear mechanisms
seen in four wheelers and not in two or three-
wheelers? Explain
11 Define the Following Term
i) Grashoff’s Law
ii) Structure
iii) Degree of Freedom
iv) Mechanism
12 Explain with neat sketch whitworth Quick Return
Mechanism
13 What is a condition of correct steering? With the
help of neat sketch explain the construction and
working of Davis Steering Gear mechanism
14 Define the following
i) Machine
ii) Kinematic Chain
iii) Kinematic Link
iv] Grashoff’s law
15 Explain the following terms with suitable examples:-
i] Completely constrained motion
ii] Incompletely constrained motion
iii] Successfully constrained motion
16 Write short note on
i) Pantograph along with its application.
ii) Scotch yoke mechanism
17 In a Oldham coupling, the distance between shaft
axes is 30 mm and speed of rotation is 600 rpm,
what is maximum speed of sliding of each tongue in
the slot?
18 Define:-
1. DOF of a body
2. DOF of a mechanism
19 Define and explain with neat sketches the various
types of constrained motions
20 Define kinematic pair and discuss various types of
kinematic pairs with examples.
21 State and explain Grubler criterion for mobility of a
planer mechanism with various applications using
lower pairs and higher pairs
22 Different mechanisms may be obtained by
inversions of the same kinematic chain. Explain the
meaning of this statement with all inversions of
single slider crank chain. Give practical application
of each inversion
23 With the help of neat sketch, explain Pecullier
straight line mechanism giving proof of the tracing
point describing exact straight line
24 Explain the working of Davis steering gear with the
help of a neat sketch. Find the inclination of track
arm in terms of wheel base and the distance
between the pivots of the axle in order to satisfy the
condition of steering.
25 Write short note on “Ackermann steering gear”
26 In a Davis steering gear the distance between the
pivots of the front axle is 120 cm and the wheel
base is 260 cm. When the vehicle is moving on a
straight path, find the inclination of track arms to
the vertical
27 A car using Ackermann steering gear has a wheel
base of 2.8m and a track of 1.5m. The track rod is
1.1m and the track arm is 0.15m. The distance
between the pivots of stub axle is 1.2m. Find the
radius of turning of inner wheels for correct
steering.
28 Write a short note on elliptical trammel. State and
explain the condition for which it will trace a circle
29 In case of an elliptical trammel, prove that any point
on the coupler rod traces perfect ellipse. Hence
locate that point on the coupler, which will trace
circle
30 Write a short note on Gnome engine
31 Compare ‘Davis’ and ‘Ackermann’ steering gear
mechanisms
32 In the Davis steering gear mechanism, the distance
between the pivots of the front axles is 1.2m. The
wheel base is 3m. When a vehicle is moving along a
straight path, find the inclination of the track arms
to the longitudinal axis, provided that the
mechanism has to satisfy the condition of correct
steering
33 In case of Davis steering gear mechanism:
1. The distance between the pivots of the front
axle = 1.5m
2. The wheel base = 5m
Find the inclination of the track arms to the
longitudinal axis, provided that the mechanism has
to satisfy the condition of correct steering
34 What is kinematic pair? Give its classification in
details.
35 Explain types of kinematic links with neat sketches
36 Explain types of kinematic joints with neat sketches
37 Explain Kutzbach criterion.
38 Differentiate between Machine and Mechanism
39 What is four bar chain mechanism? Explain any
one Inversion with neat sketch
40 Explain Beam engine with neat sketch
41 Explain Fourth Inversion of Single slider crank
mechanism with neat sketch
42 Explain Skotch yoke mechanism with neat sketch
43 Write a short note on Equivalent linkage of
mechanism
44 Calculate the number of degree of freedom of the
mechanism As shown in Fig
45 Calculate the number of degree of freedom of the
mechanism As shown in Fig
46 Calculate the number of degree of freedom of the
mechanism As shown
47 Calculate the number of degree of freedom of the
mechanism As shown
48 Calculate the number of degree of freedom of the
mechanism As shown
49 Calculate the number of degree of freedom of the
mechanism As shown
50 What are rigid and resistant bodies? Elaborate.
MCQ QUESTION BANK
Q. No Description
1 In a Kinematic chain, a quaternary joint is equivalent to:
(a) One binary joint (b) Two binary joints(c) Three binary joints (d)
Four binary joints
Ans. (c) when ‘l ’ number of links are joined at the same connection,
the joint is equivalent to
(L - 1) binary joints
2 A round bar A passes through the cylindrical hole in B as shown in the
given figure. Which one of the following statements is correct in this
regard?
a) The two links shown form a kinematic pair.
b) The pair is completely constrained.
c) The pair has incomplete constraint.
d) The pair is successfully constrained.
Ans. (c)
3 Consider the following statements
1. A round bar in a round hole form a turning pair.
2. A square bar in a square hole forms a sliding pair.
3. A vertical shaft in a footstep bearing forms a successful
constraint.
Of these statements
(a) 1 and 2 are correct
(b) 2 and 3 are correct
(c) 1 and 3 are correct
(d) 1, 2 and 3 are correct
Ans. (b)
4 Consider the following statements:
1. Lower pairs are more resistant than the higher pairs in a
plane mechanism.
2. In a 4-bar mechanism (with 4 turning pairs), when the link opposite to
the shortest link is fixed, a double rocker mechanism results.
Which of the statements given above is/are correct?
(a) Only 1 (b) Only 2 (c) Both 1 and 2 (d) Neither 1 nor 2
Ans. (c)
5 Consider the following pairs of parts:
1. Pair of gear in mesh
2. Belt and pulley
3. Cylinder and piston
4. Cam and follower
Among these, the higher pairs are
(a) 1 and 4 (b) 2 and 4 (c) 1, 2 and 3 (d) 1, 2 and 4
Ans. (a)
6 Which of the following is a higher pair?
(a) Belt and pulley (b) Turning pair (c) Screw pair (d) Sliding pair
Ans. (a) A higher pair have point or line contact.
7 Which of the following disciplines provides study of relative
motion between the parts of a machine
(a) theory of machines (b) applied mechanics (c)mechanisms (d)
kinetics
(e) kinematics
Ans: e
8 Which of the following is a lower pair
(a) ball and socket (b) piston and cylinder (c) cam and follower
(d) (a) and (b) above
(e) belt drive.
Ans: d
9 If two moving elements have surface contact in motion, such
pair is known as
(a) sliding pair (b) rolling pair
(c) surface pair (d) lower pair (e) higher pair.
Ans: e
10 The example of lower pair is
(a)shaft revolving in a bearing
(b)straight line motion mechanisms
(c)automobile steering gear
(d)all of the above
(e)none of the above.
Ans: d
11 Pulley in a belt drive acts as
(a)cylindrical pair (b)turning pair (c) rolling pair (d)sliding pair
(e)surface pair.
Ans: c
12 The example of rolling pair is
(a)bolt and nut (b)lead screw of a lathe (c)ball and socket joint (d)ball
bearing and roller bearing (e) all of the above.
Ans: d
13 A universal joint is an example of
(a)higher pair (b)lower pair (c)rolling pair (d)sliding pair (e)turning
pair.
Ans: b
14 The example of spherical pair is
(a)bolt and nut (b)lead screw of a lathe (c)ball and socket joint (d)ball
bearing and roller bearing (e)none of the above.
Ans: c
15 Cross head and guides form a
(a)lower pair (b)higher pair (c)turning pair (d)rolling pair (e)sliding
pair.
Ans: e
16 If there are L number of links in a mechanism then number of
possible inversions is equal to
(a)L+1
(b)L-1
(c)L
(d)L+2
(e)L-2.
Ans: c
17 The lower pair is a
(a)open pair (b)closed pair (c)sliding pair (d)point contact pair (e)does
not exist.
Ans: b
18 Which of the following would constitute a link
(a)piston, piston rings and gudgeon pin
(b)piston, and piston rod
(c)piston rod and cross head
(d)piston, crank pin and crank shaft
(e)piston, piston-rod and cross head.
Ans:e
19 Ackermann steering gear consists of
(a)sliding pairs
(b)turning pairs
(c)rolling pairs
(d)higher pairs
(e)lower pairs.
Ans: b
20 Oldham's coupling is the
(a)second inversion of double slider crank chain
(b)third inversion of double slider crank chain
(c)second inversion of single slider crank chain
(d)third inversion of slider crank chain
(e)fourth inversion of double slider crank chain.
Ans: b
21 The number of links in pantograph mechanism is equal to
(a) 2
(b) 3
(c) 4
(d) 5
(e) 6.
Ans:c
22 Rectangular bar in a rectangular hole is the following type of
pair
(a)completely constrained motion
(b) partially constrained motion
(c) incompletely constrained motion
(d) freely constrained motion
(e) none of the above.
Ans: a
23 Governor is used in automobile to
(a)decrease the variation of speed
(b)to control
(c)to control SN
(d)all of the above
(e)none of the above.
Ans: c
24 Idler pulley is used
(a)for changing the direction of motion of the belt
(b)for applying tension
(c)for increasing -velocity ratio
(d)all of the above
(e)none of the above.
Ans: b
25 The locus of a point on a thread unwound from a cylinder will
be
(a) a straight line
(b) a circle
(c) involute
(d) cycloid
(e) helix.
Ans: c
26 Throw of a cam is the maximum distance of the follower from
(a)base circle
(b)pitch circle
(c)root circle
(d)prime circle
(e)inner circle.
Ans: a
27 Kinematic pairs are those which have
(a)point or line contact between the two elements when in motion
(b)surface contact between the two elements when in motion
(c)elements of pairs not held together mechanically
(d)two elements that permit relative motion
(e)none of the above.
Ans: d
28 A pantograph is a mechanism with
(a)lower pairs
(b)higher pairs
(c)rolling pairs
(d)turning pairs
(e)spherical pairs.
Ans: a
29 The approximate straight line mechanism is a
(a)four bar linkage
(b)6 bar linkage
(c)8 bar linkage
(d)3 bar linkage
(e)5 bar linkage.
Ans: a
30 Peaucellier mechanism has
(a)eight links
(b)six links
(c)four links
(d)twelve links
(e)five links.
Ans: a
31 Hart mechanism has
(a)eight links
(b)six links
(c)four links
(d)twelve links
(e)five links.
Ans: b
32 The main disadvantage of the sliding pair is that it is
(a)bulky
(b)wears rapidly
(c)difficult to manufacture
(d)(a) and (b) above
(e)(a) and (c) above.
Ans: d
33 A kinematic chain requires at least
(a)2 links and 3 turning pairs
(b)3 links and 4 turning pairs
(c)4 links and 4 turning pairs
(d)5 links and 4 turning pairs
(e)none of the above.
Ans: c
34 Kinematic pairs are those which have
(a)two elements held together mechanically
(b)two elements having relative motion
(c)two elements having Coroili's component
(d)minimum of two instantaneous centers
(e)all of the above.
Ans: b
35 A ball and socket joint form a
a.turning pair
b.rolling pair
c.sliding pair
d.spherical pair
answer :- d.spherical pair
36 If a kinematic chain has 'l' links, then the number of
mechanism obtained are
a. l - 1
b. l - 2
c. l+1
d. l
answer :- d.l
37 A rigid body possesses_____degrees of freedom.
a. One b. Two c. Four d. Six
(Ans:d)
38 Which of the following is an open pair?
a. Journal bearing b. Ball and Socket joint
c. Leave screw and nut d. None of the above
(Ans:c)
39 . ________ is an inversion of Double slider crank chain.
a. Coupling rod of a locomotive b. Scotch yoke mechanism
c. Hand pump d. Reciprocating engine
(Ans:b)
40 The Kutzbach criterion for determining the number of degrees
of freedom (n) is (where l = number of links, j = number of joints
and h = number of higher pairs)
a. n = 3(l-1)-2j-h b. n = 2(l-1)-2j-h
c. n = 3(l-1)-3j-h d. n = 2(l-1)-3j-h
(Ans:a)
41 What is the number of instantaneous centres for an eight link
mechanism?
a. 15 b. 28 c. 30 d. 8
(Ans:b)
42 Consider the following mechanisms:
1. Oscillating cylinder engine mechanism
2. Toggle mechanism
3. Radial cylinder engine mechanism
4. Quick return mechanism
Which of the above are inversions of slider crank mechanism?
1. 1, 2 and 4
2. 2, 3 and 4
3. 1, 2 and 3
4. 1, 3 and 4
(Ans: d)
43 The kinematic chain shown in the above figure is a
(a) structure
(b) mechanism with one degree of freedom
(c) mechanism with two degree of freedom
(d)mechanism with more than two degrees of
freedom
Ans. (d)
44 In the given figure, ABCD is a four-bar mechanism. At the
instant shown, AB and CD are vertical and BC is horizontal AB
is shorter than CD by 30 cm. AB is rotating at 5 radius and CD
is rotating at 2 rad/s. The length of AB is
(a) 10cm (b) 20 cm (c) 30 cm (d) 50 cm
Ans. (b) 5L=2(L+30), 3L=60, L=20
45 In a single slider four-bar linkage, when the slider is fixed, it
forms a mechanism of
(a) hand pump (b) reciprocating engine
(c) quick return (d) oscil1ating cylinder
Ans. (a)
46 The type of quick return mechanism employed mostly in
shaping machines is:
(a) DC reversible motor (b) Fast and loose pulleys(c) Whitworth
motion (d) Slotted link mechanism
Ans. (d)
47 The Whitworth quick return mechanism is formed in a slider-
crank chain when the
(a) coupler link is fixed (b) longest link is a fixed link(c) slider is
a fixed link (d) smallest link is a fixed link
Ans. (d)
48 ABCD is a mechanism with link lengths AB = 200, BC = 300, CD
= 400 and DA =350. Which one of the following links should be
fixed for the resulting mechanism to be a double crank
mechanism? (All lengths are in mm)
a)A B (b) BC (c) CD (d) DA
Ans. (c)
49 Scotch yoke mechanism is used to generate
(a) sine functions (b) square roots (c) logarithms (d) inversions
Ans. (a)
50 Which one of the following is an exact straight line mechanism
using lower pairs?
(a) Watt's mechanism (b) Grasshopper mechanism
(c) Robert's mechanism (d) Paucellier’s mechanism
Ans. (d)
UNIT-II
A] Theory Question Bank
Q.
No
Description
01 Explain the difference between static and dynamic force analysis
02 Explain the following
i) Inertia
ii) D’Alembert’s Principle
iii) SHM
iv) Radius of Gyration
03 What is the difference between simple pendulum and compound
pendulum
04 Derive relation for periodic time of oscillation of a connecting rod
(Compound Pendulum)
05 Derive relation for periodic time of oscillation of a bar when it is
suspended by two long strings attached at its ends (Bifilar
Suspension)
06 Derive relation for periodic time of oscillation of a circular disc when
it is suspended by three long strings attached at its periphery
(Trifilar Suspension)
07 Explain the concept of Dynamically (or Kinetically) Equivalent
System
08 Sometimes why it is required to have ‘Correction Couple’ for two
mass dynamically equivalent system
09 How to calculate ‘Correction Couple’ for two mass dynamically
equivalent system
10 Neglecting Inertia force derive a relation for Piston Side Thrust
11 Neglecting Inertia force derive a relation for Tangential force acting
on crank pin
12 Considering the Inertia Forces derive a relation for Torque exerted
on the crank shaft due to inertia forces
13 Considering the Inertia Forces derive a relation for Torque exerted
on the crank shaft due to correction couple
14 Considering the Inertia Forces derive a relation for Torque exerted
on the crank shaft due to weight of mass m2 at big end centre
15 Explain T-θ diagram for a single cylinder four stroke IC Engine
16 Describe Types of Friction
17 Describe Laws of Dry Friction
18 Derive a relation for Limiting angle of Friction
19 Describe Friction in Turning Pairs
20 Describe Friction Circle
21 Describe Friction Axis of a Link
22 Explain friction circle. Deduce an expression for the radius of friction
circle in terms of the journal and the angle of friction.
23 Compare compound pendulum and bifilar pendulum suspension
method of finding the mass moment of inertia of rod like body.
24 Draw and explain turning moment diagram of a 4 stroke cylinder
Engine. State significance of it
25 A connecting rod of mass of 3.5 kg is suspended by two wires each of
2 m length. The wires are attached to the rod at points 150 mm on
either side of the centre of gravity. if the connecting rod makes 35
oscillations in 60 seconds. Find the radius of gyration and the mass
moment of inertia of the connecting rod about its centre of gravity.
26 A machine component of mass 5 kg is placed on a rectangular
horizontal platform which is suspended by two equal strings of
length 1.25 mm from rigid support and equidistance of 125 from C.G.
of the platform .when the mass of centre of the component coincides
with the axis of the platform ,it takes 45 seconds for 15 oscillations.
The platform alone has a mass of 1.5 kg and takes 60 seconds for 15
oscillations. Find the radius of gyration and the mass moment of
inertia of the machine component about an axis through its mass
centre.
27 The mass of a connecting rod of an engine 5 kg and is 600 mm long
between the centers .its C.G. IS 400mm from the centre of small end
about which the connecting rod oscillates in a vertical plane .the
rod is found by experimentally to complete 50 oscillations in 72
seconds . find the radius of gyration and the mass moment of inertia
of the connecting rod about an axis through its centre of gravity.
What is the length of the equivalent simple pendulum?
28 A connecting rod of mass of 1.7 kg is suspended by two wires each of
1.5 m length. The wires are attached to the rod at points 120 mm on
either side of the centre of gravity. if the connecting rod makes 25
oscillations in 40 seconds .find the radius of gyration and the mass
moment of inertia of the connecting rod about a vertical axis
through the centre of gravity.
29 The wheel of vehicle complete with tyre is suspended at three
vertical strings each equal 1.5 m long, equally spaced the periphery
of the tyre at a radius of 350 mm. the oscillations of small torsional
vibration of the wheel is 20 cycles per minute. Find the radius of
gyration of wheel about its axis.
30 The connecting rod of an engine has a length equal to 220 mm
between centers and has a mass equal to 2 kg. Its centre of gravity is
at 150 mm from the small end centre and the moment of inertia of
0.02 kg-m2about its centre of gravity.
Find :
(i)the two mass dynamically equivalent system when one mass is
located at the small end centre,
(ii)the correction couple, if two masses are placed at the two ends
and the angular acceleration of the connecting rod is 20,000
rad/s2anticlockwise
31 A high speed vertical engine has a connecting rod length five times
the crank which is 60 mm. Its mass is 3 kg and has a C.G. 200mm
from the small end bearing. When suspended in a small end bearing,
it makes 50 oscillations in 52 seconds. The reciprocating parts have
a mass of 1.5 kg. Determine the torque exerted on the crankshaft
due to inertia of the moving parts when the crank makes an angle of
135º with TDC, and speed of rotation is 1200 rpm
32 A single cylinder horizontal steam engine has a stroke of 0.75 m and
a connecting rod 1.8 m long. The mass of reciprocating parts is 520
kg and that of the connecting rod is 230 kg. Centre of gravity of the
connecting rod is 0.8 m from crank pin and the moment of inertia
about an axis through the centre of gravity perpendicular to the
plane of motion is 100 kg.m2 . For an engine speed of 90 rpm and a
crank position of 45° from the IDC, determine the torque on the
crankshaft due to the inertia of these parts by analytical method
33 A connecting rod is suspended from a point 25 mm above the small
end centre and 650 mm above its C.G. It makes 20 oscillations in 35
seconds.
Find dynamically equivalent two masses when one mass is placed at
small end centre. Take mass of connecting rod as 40 kg
34 A rigid link 500 mm long, mass 2 kg and radius of gyration 200 mm
.replace this link by dynamically equivalent system of two masses
located at the ends of the link.
35 Explain dynamic equivalence of two mass systems, for a connecting
rod of an IC engine having mass ‘m’ and radius of gyration ‘k’. Obtain
a two mass dynamically equivalent system, having one of the two
masses at the small end. How dynamical equivalence is achieved if it
is required that the other mass located at the big end
36 An IC engine has a stroke of 100 mm and bore of 80 mm. The
connecting rod is 160 mm between centers and has total mass of 1.3
kg. Its center of mass is 130 mm away from small end center and
radius of gyration about the mass center is 75 mm. The reciprocating
mass is 1.8 kg. Determine magnitude of resultant forces on the crank
pin, neglecting friction and gravity, when the crank is 300 after the
TDC position and rotating at 1600 rpm clockwise. The gas pressure
on the piston is 2 N/mm2
37 The connecting rod of an engine has length equal to 200 mm
between centers and has mass equal to 3.5 kg. Its CG is at 80 mm
from the big end centre and the radius of gyration about an axis
through CG is 100 mm. Determine :
(i) The two mass dynamically equivalent system when one mass is
placed at the small end.
(ii) The correction couple if two masses are placed at the two ends
and angular acceleration of connecting rod is 100 rad/s2 clockwise.
38 The connecting rod of a vertical reciprocating engine is 2000 mm
long between centres and its weights 250 kg. The mass centre is 800
mm from the big end centre. When it suspended as a pendulum from
the small end axis, it makes 8 complete oscillations in 22 seconds.
The crank is 400 mm long and rotates at 200 rpm. Determine by
analytical method :
(i) The mass moment of inertia of connecting rod about an axis
through as mass centre.
(ii) The inertia torque exerted on the crank shaft, when the crank has
turned through 40° from the top dead centre and piston is moving
downwards.
39 A connecting rod is suspended from a point 25 mm above the centre
of small end, and 650 mm above its centre of gravity, its mass being
37.5 kg. When permitted to oscillate, the time period is found to be
1.87 seconds. Find the dynamical equivalent system constituted of
two masses, one of which is located at the small end centre.
40 A vertical engine running at 1200 r.p.m. with a stroke of 110 mm has
a connecting rod 250 mm between centers and mass 1.25 kg. The
mass centre of the connecting rod is 75 mm from the big end centre
and when suspended as pendulum from the gudgeon pin axis makes
21 complete oscillations in 20 seconds :
(i) Calculate the radius of gyration of the connecting rod about an
axis through its mass centre.
(ii) When the crank is at 40º from the top dead centre and the piston
is moving downwards, find analytically, the acceleration of the
piston and the angular acceleration of the connecting rod. Hence
find the inertia torque exerted on the crankshaft. To make the two-
mass system to be dynamically equivalent to the connecting rod,
necessary correction torque has to be applied and since the engine is
vertical gravity effects are to be considered.
41 The connecting rod of an engine has a length equal to 220 mm
between centers and has a mass equal to 2 kg. Its centre of gravity is
at 150 mm from the small end centre and the moment of inertia of
0.02 kg-m2about its centre of gravity.
Find :
(I) the two mass dynamically equivalent system when one mass is
located at the small end centre,
(II) The correction couple, if two masses are placed at the two ends
and the angular acceleration of the connecting rod is 20,000
rad/s2anticlockwise.
42 Explain dynamic equivalence of two mass systems, for a connecting
rod of an IC engine having mass ‘m’ and radius of gyration ‘k’. Obtain
a two mass dynamically equivalent system, having one of the two
masses at the small end. How dynamical equivalence is achieved if it
is required that the other mass located at the big.
43 The following data refers to horizontal reciprocating engine:
Mass of reciprocating parts = 100 Kg,
Stroke Length = 200 mm,
Speed of engine = 900 rpm clockwise, Connecting rod mass = 80 Kg.
Length between centers = 400 mm,
Distance of C.G. from end center = 160 mm,
Radius of gyration of connecting rod about an axis through C.G = 120
mm.
Determine analytically the inertia torque on crankshaft when the
crank has turned 400
from I.D.C
44 The following data refers connecting rod of a reciprocating engine:
Mass = 55 Kg,
Diameter of the small end bearing= 75 mm
Diameter of the big end bearing= 100 mm
Distance between bearing centers = 850 mm,
Time of oscillation when the connecting rod is suspended from small
end 1.83 seconds. Time of oscillation when the connecting rod is
suspended from big end 1.68 second.
Determine
1) The radius of gyration of connecting rod about an axis through
C.G and perpendicular to the plane of oscillation
2) The moment of inertia of the rod about the same axis.
45 The piston diameter of an internal combustion engine is 125Mm and
the stroke is 220 mm. The connecting rod is 4.5 times the crank
length and has a mass of 50 kg. The mass of the reciprocating parts
is 30 kg. The centre of mass of connecting rod is 170 mm from the
crank pin centre and the radius of gyration about an axis through the
centre of mass is 148 mm. The engine runs at 320 rpm.
Find the magnitude and the direction of the inertia force and the
corresponding torque on the crankshaft when the angle turned by
the crank is 140º from the inner dead centre.
46 A gear of mass 4.5 kg is placed on a horizontal circular platform
whose mass is 2.5 kg. it is suspended by three equal wires, each 1.5
m long ,from a rigid support .the wires are equally spaced round the
circumference of a circle of 110 mm radius .when the C.G. of the
gear coincides with the axis of the circular platform ,the platform
makes 12 angular oscillations in 30 seconds .determine the mass
moment of inertia of combined system about an axis through its C.G.
47 A rectangular cross section bar is suspended horizontally with the
help of two equal strings equidistance from C.G. the length o0f each
string is 300 mm and the distance between is each string and C.G. of
the bar is 175 mm. the bar cross section is 30 mm x 20 mm and the
length of the bar is 700 mm. the bar mass density is 7.8 gm / cc .
Two identical cylindrical components each with mass 300 gm are
kept on the bar on either sides of the C.G. of the bar. The distance
between C. G. of the bar and the C. G. of the component is 225 mm.
The bar together with the components is made to oscillate in the
horizontal plane about the C. G. of the bar. The number of
oscillations is 90 in 150 seconds. Assuming amplitude of oscillations
as small calculate radius of gyration of the cylindrical components
about the C. G.
48 In a slider crank mechanism, the crank is 200 mm long and
connecting rod is 750 mm long. The piston is 80 mm in diameter and
a pressure difference of 2 MPa exists between two sides of piston
when the crank is moved through 45 degrees from top dead centre
position find
i) Thrust in connecting rod
ii) Reaction from guide
iii) Torque active on crank shaft
iv) Load on main bearings
49 The mass of reciprocating parts of a steam engine is 225 kg.
Diameter of the cylinder is 400 mm. Length of the Stroke is 500 mm
and the ration of the connecting rod to crank is 4.2 When the crank
is at inner dead centre, the difference in the pressure of the two
sides of the piston is 5 bar. At what speed must the engine should
run so that the thrust in the connecting rod in this position is equal
to 5200 N
50 The obliquity ratio of a vertical reciprocating engine is 4.5 The
engine bore and stroke is 75 mm and 90 mm respectively. The mass
of the reciprocating parts is 1.2 kg. The gas pressure intensity is 5.5
bar when it has moved through 50 degrees from the i. d. c. on its
power stroke. Determine:
i) Piston Effort
ii) Net load on gudgeon pin and crank pin
iii) Thrust in cylinder walls
iv) Thrust on the crank bearing
Assuming speed of the engine as 2200 rpm.
Calculate at what speed the load on gudgeon pin and the crank pin
be zero.
MCQ
Q.
No
Description
1 4. The angle which the normal
reaction makes with the
resultant reaction is called …...
A. normal angle
B. angle of friction
C. coff. of friction
D. None of the above
Answer- B
2 15. A body of weight W is required
to move up the rough inclined
plane whose angle of inclination
with the horizontal is α. The
effort applied parallel to the
plane is given by (where μ = tan
φ = Coefficient of friction
between the plane and the body)
A. P = W tan α
B. P = W tan (α + φ)
C. P = W (sin α + μ cos α)
D. P = W (cos α + μ sin α)
Answer: C
3 The essential condition of placing
the two masses, so that the system
becomes dynamically equivalent, is
(where l1 and l2 = Distance of two
masses from the centre of gravity of
the body, and kG = Radius of
gyration of the body)
A.l1 = kG
B.l2 = kG
C.l1l2 = kG
D.l1l2 = kG2
Answer: D
4 Which of the following statements
regarding laws governing the
friction between dry surfaces are
correct?
A. The friction force is dependent
on the materials of the contact
surfaces.
B. The friction force is directly
proportional to the normal force.
C. The friction force is independent
of me area of contact.
D.all of the above
Answer: D
5 The length of a simple pendulum
which gives the same frequency as
the compound pendulum, is
A.kG + l1
B.kG2 + l1
C.
D.
Answer: C
6 The friction experienced by a body,
when at rest, is known as…..
A. static friction
B. Dynamic friction
C. Both A &B
D. None of the above
Answer: A
7
The inertia force is equal to the …….in magnitude, but opposite in
direction.
A.Accelerating force
B.Velocity
C. Mass moment of inertia
D.All of the above
Answer: A
8 Which of the following statements
regarding laws governing the
friction between dry surfaces are
correct?
A. The friction force is dependent on
the materials of the contact
surfaces.
B. The friction force is directly
proportional to the normal force.
C. The friction force is independent
of me area of contact.
D.all of the above
Answer: D
9 The acceleration of the particle
moving with simple harmonic
motion from the mean position is.
A. Inversely proportional to the
displacement of the particle
B.Directly proportional to the
displacement of the particle.
C.Directly proportional to
frictional force
D. All of the above
Answer: B
10 When a body moves with simple
harmonic motion, the product of its
periodic time and frequency is equal
to
A. zero
B. one
C. π/2
D. π
Answer: B
11. The minimum force required to slide a body of weight W on a rough
horizontal plane is
A. W sin θ
B. W cos θ
C. W tan θ
D. W cosec θ
Answer: A
12
Correction couple is applied when ---
A. If the Distance of m2 mass is selected arbitrarily
B. If the Distance of m1 mass is selected arbitrarily
C. Both masses m1 & m2 have to be selected arbitrarily
D. All of the above
Answer- C
13 While analyzing the inertia effect of connecting rod of slider crank
mechanisms ,mass m1 is placed at small end which is –
A.PISTON SIDE
B.Crank side
C. Both A & B
D.None of the above
Answer - A
14 The connecting rod of an engine has a length equal to 25cm
between centers and has a mass equal to 3 kg. Its centre of gravity
is at 175 mm from the small end centre and the moment of inertia
of 0.025 kg-m2about its centre of gravity. when any one mass is
located at small end, position of the second mass for dynamically
equivalent system is …mm
A. 55.2
B. 33.8
C. C.65.9
D. 47.6
Answer – D
15 In static force analysis Fp.tanφ is the equation of force
A.gas force on piston
B. piston side thrust
C. piston effort
D. inertia force due to piston
Answer- B
16 In a slider crank mechanism, The crank is 0.3 m long and
connecting rod is 0.85 m long .the piston is of 9 cm in diameter
and gas pressure acting on the piston is 5Mpa .the piston effort is
…..KN.
A.45.78
B. 31.81
C.83.19
D. 19.10
Answer- B
17
In case of ……engine the effort of weight of reciprocating parts is
also considered.
A. Vertical
B. Horizontal
C. Both A &B
D. None of the above.
Answer- A
18 Normal reaction acting on the cylinder wall is also called as
A. Piston side thrust
B. Piston effort
C.Net axial force on piston
D. None of the above
Answer- A
19 Radial force acting on crank shaft is also called as …
A. Torque on the crank
B. Radial force acting on the crank
C. Tangential force on the crank
D. All of the above
Answer- C
20 Turning moment diagram is also called as…
A.T-θ diagram
B. Crank effort diagram
C. Stress-strain diagram
D. Both A&B
Answer- D
21
When T-θ diagram is positive, the crankshaft ……
A. Accelerates
B. Retards
C. Constant
D. Linear
Answer- B
22 In case of three cylinder engine the crank placed at …..to each
other.
A.00
B.900
C.1200
D.2700
Answer- C
23 In case of horizontal engine ,if the crank makes an angle of 1400
and rotates clockwise with IDC then torque due to mass at big end
is
A. Anticlockwise
B. Clockwise
C. Both A&B
D. None of the above
Answer- B
24
A shaft of radius 50 mm rotates in a bearing. If the coefficient of
friction µ=0.25,then the radius of friction circle is -----
A. 0.025 m
B. 0.075 m
C. 0.0955m
D. 0.0125 m
Answer- D
25 A shaft of radius 75 mm rotates in a bearing at 400 rpm. IF µ=0.35,
then the diameter of friction circle is -----cm
A. 10.00
B. 10.50
C. 2.12
D. 5.25
Answer- D
26
Friction torque is T= -----
A. P x (r/µ)
B. P x (r.µ)
C. P x (r-µ)
D. All of the above
Answer- B
27 Journal is also called as ---
A. Hub
B. Coupling
C. Bearing
D. Shaft
Answer- D
28 A 300 N force is required to pull the body resting on a horizontal
plane .the force is inclined at an angle of 300 with horizontal. If
µ=0.1332, then the mass of the body is -----kg.
A.214.5
B. 500
C.144.29
D.125.3
Answer- A
29 Sliding friction is the type of ----friction
A. Film Friction
B. Greasy Friction
C. Dry Friction
D. Kinematic Or Dynamic Friction
Answer-C
30 MMI of a pulley is found by using ----method
A. Simple pendulum
B. Bifilar suspension
C. Trifilar suspension
D. Compound pendulum
Answer-C
31 Time period of oscillations of torsional pendulum does not depend
on ---
A. Length of each wire