List Of Objective Questions On Theory Of Machines
1.In higher pair, the relative motion is
purely turning
purely sliding
purely rotary
purely surface contact
combination of sliding and turning.
ANSWER : : combination of sliding and turning.
2.If two moving elements have surface contact in motion, such pair is known as
sliding pair
rolling pair
surface pair
lower pair
higher pair.
ANSWER : : higher pair.
3.The example of rolling pair is
bolt and nut
lead screw of a lathe
ball and socket joint
ball bearing and roller bearing
all of the above.
ANSWER : : ball bearing and roller bearing
4.The lower pair is a
open pair
closed pair
sliding pair
point contact pair
does not exist.
ANSWER : : closed pair
5.If some links are connected such that motion between them can take place in more than one direction, it is called
incompletely constrained motion
partially constrained motion
completely constrained motion
successfully constrained motion
none of the above.
ANSWER : : incompletely constrained motion
6.Which of the following is a lower pair
ball and socket
piston and cylinder
cam and follower
(a) and (b) above
belt drive.
ANSWER : : (a) and (b) above
7.Which of the following disciplines provides study of the relative motion between the parts of a machine and the forces acting on the parts
theory of machines
applied mechanics
mechanisms
kinetics
kinematics.
ANSWER : : theory of machines
8.Which of the following disciplines provides study of relative motion between the parts of a machine
theory of machines
applied mechanics
mechanisms
kinetics
kinematics.
ANSWER : : kinematics.
9.A circular bar moving in a round hole is an example of
incompletely constrained motion
partially constrained motion
completely constrained motion
successfully constrained motion
none of the above
ANSWER : : incompletely constrained motion
10.Any point on a link connecting double slider crank chain will trace a
straight line
circle
ellipse
parabola
hyperbola.
ANSWER : : ellipse
11.Pitch point on a cam is
any point on pitch curve
the point on cam pitch curve having the maximum pressure angle
any point on pitch circle
the point on cam pitch curve having the minimum pressure angle
none of the above.
ANSWER : : the point on cam pitch curve having the maximum pressure angle
12.Rectilinear motion of piston is converted into rotary by
cross head
slider crank
connecting rod
gudgeon pin
four bar chain mechanism.
ANSWER : : slider crank
13.A universal joint is an example of
higher pair
lower pair
rolling pair
sliding pair
turning pair.
ANSWER : : lower pair
14.Pulley in a belt drive acts as
cylindrical pair
turning pair
rolling pair
sliding pair
surface pair.
ANSWER : : rolling pair
15.Automobile steering gear is an example of
higher pair
sliding pair
turning pair
rotary pair
lower pair.
ANSWER : : lower pair.
16.If there are L number of links in a mechanism then number of possible inversions is equal to
L + 1
L – 1
L
L + 2
L – 2.
ANSWER : : L
17.The example of spherical pair is
bolt andnut
lead screw of a lathe
ball and socket joint
ball bearing and roller bearing
none qf the above.
ANSWER : : ball and socket joint
18.Kinematic pairs are those which have two elements that
have line contact
have surface contact
permit relative motion
are held together
have dynamic forces.
ANSWER : : permit relative motion
19.Cross head and guides form a
lower pair
higher pair
turning pair
rolling pair
sliding pair.
ANSWER : : sliding pair.
20.Which of the following has sliding motion
crank
connecting rod
crank pin
cross-head
cross head guide.
ANSWER : : cross-head
21.The values of velocity and acceleration of piston at near dead center for a slider-crank mechanism will be
0, and more than co2r
0, and less than coV
0, 0
cor, 0
none of the above.
ANSWER : : 0, and more than co2r
22.The type of pair formed by two elements which are so connected that one is constrained to turn or revolve about a fixed axis of another element is known as
turning pair
rolling pair
sliding pair
spherical pair
lower pair,
ANSWER : : turning pair
23.The example of lower pair is
shaft revolving in a bearing
straight line motion mechanisms
automobile steering gear
all of the above
none of the above.
ANSWER : : all of the above
24.Theipurpose of a link is to
transmit motion
guide other links
act as a support
all of the above
none of the above.
ANSWER : : all of the above
25.The advantage of the piston valve over D-slide valve is that in the former case
wear is less
power absorbed is less
both wear and power absorbed are low
the pressure developed being high provides tight sealing
there is overall economy of initial cost, maintenance and operation.
ANSWER : : both wear and power absorbed are low
26.The number of links in pantograph mechanism is equal to
2
3
4
5
6.
ANSWER : : 4
27.Flexible coupling is used because
it is easy to disassemble
it is easy to engage and disengage
it transmits shocks gradually
it prevents shock transmission and eliminates stress reversals
it increases shaft life.
ANSWER : s: d
28.Rectangular bar in a rectangular hole is the following type of pair
completely constrained motion
partially constrained motion
incompletely constrained motion
freely constrained motion
none of the above.
ANSWER : : completely constrained motion
29.Shaft revolving in a bearing is the following type of pair
lower pair
higher pair
spherical pair,
cylindrical pair
bearing pair.
ANSWER : : lower pair
30.With single Hooke’s joint it is possible to connect two shafts, the axes of which have an angular misalignment up to
10�
20�
30�
40�
60�.
ANSWER : : 40�
31.In problem 47, the chain is constrained when
L.H.S. = R.H.S.
L.H.S. < R.H.S. L.H.S. > R.H.S.
there is no such criterion for checking above requirement
none of the above.
ANSWER : : L.H.S. = R.H.S.
32.Relationship between the number of links (L) and number of pairs (P) is
P = 2L-4
P = 2L + 4
P = 2L+2
P = 2L-2
P = L-4.
ANSWER : : P = 2L+2
33.A mechanism is an assemblage of
two links
three links
four links or more than four links
all of the above
none of the above.
ANSWER : : four links or more than four links
34.Davis steering gear consists of
sliding pairs
turning pairs
rolling pairs
higher pairs
lower pairs.
ANSWER : : sliding pairs
35.Ackermann steering gear consists of
sliding pairs
turning pairs
rolling pairs
higher pairs
lower pairs.
ANSWER : : turning pairs
36.Which of the following would constitute a link
piston, piston rings and gudgeon pin
piston, and piston rod
piston rod and cross head
piston, crank pin and crank shaft
piston, piston-rod and cross head.
ANSWER : : piston, piston-rod and cross head.
37.Which of the following mechanism is obtained from lower pair
gyroscope
pantograph
valve and valve gears
generated straight line motions
all of the above.
ANSWER : : all of the above.
38.49. In problem 47, the chain is unconstrained when
L.H.S. = R.H.S.
L.H.S. > R.H.S.
L.H.S. < R.H.S.
there is no such criterion for checking above requirement
none of the above.
ANSWER : : L.H.S. < R.H.S.
39.Oldham’s coupling is the
second inversion of double slider crank chain
third inversion of double slider crank chain
second inversion of single slider crank chain
third inversion of slider crank chain
fourth inversion of double slider crank chain.
ANSWER : : third inversion of double slider crank chain
40.Sense of tangential acceleration of a link
is same as that of velocity
is opposite to that of velocity
could be either same or opposite to velocity
is perpendicular to that of velocity
none of the above.
ANSWER : : could be either same or opposite to velocity
41.Elements of pairs held together mechanically is known as
closed pair
open pair
mechanical pair
rolling pair
none of the above.
ANSWER : : closed pair
42.A completely constrained motion can be transmitted with .
1 link with pin joints
2 links with pin joints
3 links with pin joints
4 links with pin joints
all of the above.
ANSWER : : 4 links with pin joints
43.The Klein’s method of construction for reciprocating engine mechanism
is based on acceleration diagram
is a simplified form of instantaneous center method
utilities a quadrilateral similar to the diagram of mechanism for reciprocating engine
enables determination of Corioli’s component
none of the above.
ANSWER : : utilities a quadrilateral similar to the diagram of mechanism for reciprocating engine
44.A slider crank chain consists of following numbers of turning and sliding pairs
I, 3
2, 2
3, 1
4, 0
0, 4.
ANSWER : : 3, 1
45.A foot step bearing and rotor of a vertical turbine form examples of
incompletely constrained motion
partially constrained motion
completely constrained motion
successfully constrained motion
none of the above.
ANSWER : : partially constrained motion
46.The Scott-Russell mechanism consists of
sliding and turning pairs
sliding and rotary pairs
turning and rotary pairs
sliding pairs only
turning pairs only.
ANSWER : : sliding and turning pairs
47.The type of coupling used to join two shafts whose axes are neither in same straight line nor parallel, but intersect is
flexible coupling
universal coupling
chain coupling
Oldham’s coupling
American coupling.
ANSWER : : universal coupling
48.The tendency of a body to resist change from rest or motion is known as
mass
friction
inertia
resisting force
resisting torque.
ANSWER : : inertia
50.The Hooke’s joint consists of :
two forks
one fork
three forks
four forks
five forks.
ANSWER : : two forks
51.To obviate axial thrust, following gear drive is used
double helical gears having opposite teeth
double helical gears having identical teeth
single helical gear in which one of the teeth of helix angle a is more
mutter gears
none of the above.
ANSWER : : double helical gears having opposite teeth
52.TJie horse power transmitted by a belt is dependent upon
tension on tight side of belt
tension on slack side of belt
radius of pulley
speed of pulley
all of the above.
ANSWER : : all of the above.
53.The moment on the pulley which produces rotation is called
inertia
momentum
moment of momentum
work
torque.
ANSWER : : torque.
54.In automobiles the power is transmitted from gear box to differential through
bevel gear
universal joint
Hooke’s joint
Knuckle joint
Oldham’s coupling.
ANSWER : : Hooke’s joint
55.To transmit power from one rotating shaft to another whose axes are neither parallel nor intersecting, use
spur gear
spiral gear
bevel gear
worm gear
crown gear.
ANSWER : : worm gear
56.For fluctuating loads, welsuited bearing is
ball bearing
roller bearing
needle roller bearing
thrust bearing
sleeve bearing.
ANSWER : : needle roller bearing
57.The Ackermann steering mechanism is preferred to the Davis type in automobiles because
the former is mathematically accurate
the former is having turning pair
the former is most economical
the former is most rigid
none of thfr above.
ANSWER : : the former is having turning pair
58.In elliptical trammels
all four pairs are turning
three pairs turning and one pair sliding
two pairs turning and two pairs sliding
one pair turning and three pairs sliding
all four pairs sliding.
ANSWER : : two pairs turning and two pairs sliding
59.Typewriter constitutes
machine
structure
mechanism
inversion
none of the above.
ANSWER : : mechanism
60.If D1 and D2 be the diameters of driver and driven pulleys, then belt speed is proportional to
D1/D2
D2/D1
1-D2.
D1
D1+D2.
ANSWER : : D1
61.In an ideal machine, the output as compared to input is
less
more
equal
may be less or more depending on efficiency
always less.
ANSWER : : equal
62.Creep in belt drive is due to
material of the pulley
material of the belt
larger size of the driver pulley
uneven extensions and contractions due to varying tension
expansion of belt.
ANSWER : : uneven extensions and contractions due to varying tension
63.In multi-V-belt transmission, if one of the belt is broken, we have to change the
broken belt
broken belt and its adjacent belts
all the belts
there is no need of changing any one as remaining belts can take care of transmission of load
all the weak belts.
ANSWER : : all the belts
64.In gramophones for adjusting the speed of the turntable, the following type of governor is commonly employed
Hartung governor
Wilson Hartnell governor
Pickering governor
Inertia governor
none of the above.
ANSWER : : Pickering governor
65.Throw of a cam is the maximum distance of the follower from
base circle
pitch circle
root circle
prime circle
inner circle.
ANSWER : : base circle
66.Idler pulley is used
for changing the direction of motion of the belt
for applying tension
for increasing -velocity ratio
all of the above
none of the above.
ANSWER : : for applying tension
67.The locus of a point on a thread unwound from a cylinder will be
a straight line
a circle
involute
cycloid
helix.
ANSWER : s: c
68.Crowning on pulleys helps
in increasing velocity ratio
in decreasing the slip of the belt
for automatic adjustment of belt position so that belt runs centrally
increase belt and pulley life
none of the above.
ANSWER : : for automatic adjustment of belt position so that belt runs centrally
69.When a ship travels in a sea, which of the effect is more dangerous
steering
pitching
rolling
all of the above
none of the above.
ANSWER : : pitching
70.Governor is used in automobile to
decrease the variation of speed
to control
to control SN
all of the above
none of the above.
ANSWER : : to control SN
71.For S.H.M. cam, the acceleration of the follower at the ends of the stroke and aimidstroke respectively, is
maximum and zero
zero and maximum
minimum and maximum
zero and minimum
maximum and minimum.
ANSWER : : maximum and zero
72.Which of the following is false statement in respect of differences between machine and structure
Machines transmit mechanical work, whereas structures transmit forces
In machines, relative motion exists be-tween its members, whereas same does hot exist in case of structures
Machines modify movement and work, whereas structures modify forces
Efficiency of machines as well as structures is below 100%
Machines are run by electric motors, but structures are not.
ANSWER : : Efficiency of machines as well as structures is below 100%
73.The indicator using Watt mechanism is known as
Thompson indicator
Richard indicator
Simplex indicator
Thomson indicator
none of the above.
ANSWER : : Richard indicator
74.The e.g. of a link in any mechanism would experience
no acceleration
linear acceleration
angular acceleration
both angular and linear accelerations
none of the above.
ANSWER : : both angular and linear accelerations