# 360+ Mechatronics Solved MCQs

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1.

## Which of the following is incorrect regarding inertia force?

A. imaginary force
B. acts upon a rigid body
C. brings the body to equilibrium
D. same direction as of accelerating force
Answer» D. same direction as of accelerating force
2.

A. true
B. false
3.

A. i. α/f
B. i. α/m.g
C. i/m.k
D. m.k/i
4.

## D-Alembert’s principle is used for which of the following?

A. change static problem into a dynamic problem
B. change dynamic problem to static problem
C. to calculate moment of inertia of rigid bodies
D. to calculate angular momentum of a system of masses
Answer» B. change dynamic problem to static problem
5.

## 2 D ALEMBERT'S PRINCIPLE - DYNAMIC ANALYSIS IN RECIPROCATING ENGINES

A. reversed effective force
B. net force
C. coriolis force
D. resultant force
6.

## A body remains in equilibrium if

A. inertia force is applied in the same direction to the resultant force
B. inertia force is applied in the direction opposite to the resultant force
C. inertia force is applied in the direction perpendicular to the resultant force
D. inertia force is applied in the direction parallel to the resultant force
Answer» B. inertia force is applied in the direction opposite to the resultant force
7.

A. true
B. false
8.

A. i.α/f
B. i.α/m.g
C. i/m.k
D. m.k/i
9.

## Considering a four bar chain with each link having linear and angular acceleration, applying D-Alembert’s principle will never result in which of the following member?

A. 2- force member
B. 3- force member
C. 4 – force member
D. non accelerating member
10.

A. true
B. false
11.

A. tdc to bdc
B. bdc to tdc
C. midway to tdc
D. bdc to midway
12.

A. tdc to bdc
B. bdc to tdc
C. midway to tdc
D. bdc to midway
13.

## When the piston is accelerated, the piston effort is given by which of the following the equation?

A. f(l) – f(i)
B. f(l) + f(i)
C. f(l) ± f(i)
D. f(l) – f(i) + r(f)
14.

## In the presence of frictional resistance, the expression for piston effort is

A. f(l) – f(i)
B. f(l) + f(i)
C. f(l) ± f(i) – r(f)
D. f(l) – f(i) + r(f)
Answer» C. f(l) ± f(i) – r(f)
15.

## Crank effort is the product of crank pin radius and

A. thrust on sides
B. crankpin effort
C. force acting along connecting rod
D. piston effort
16.

A. true
B. false
17.

A. 17.56 n
B. 19.2 n
C. 18.53 n
D. 18.00 n
18.

A. 88000 n
B. 90560 n
C. 78036 n
D. 88357 n
19.

A. true
B. false
20.

## For a multicylinder engine, the coefficient of fluctuation of speed would vary with

A. number of cylinders
B. remains unaffected
C. length of connecting rod
D. input temperature
21.

A. the gases
B. on the gases
C. piston wall
D. valve
22.

## For a 4 cylinder engine, when the pressure inside the cylinders exceeds the atmospheric pressure then.

A. work is done by the gases
B. work is done on the gases
C. work is done on the piston wall
D. work is done by the piston wall
Answer» A. work is done by the gases
23.

## In a punching press, which of the following quantity is constant?

B. torque
C. angular velocity
D. angle of rotation
24.

A. true
B. false
25.

## The maximum shear force required for punching depends on

A. sheared area
B. length of the plate
C. speed of the flywheel
26.

A. 26.7 kn
B. 53.4 kn
C. 13.35 kn
D. 106.8 kn
27.

A. s=r
B. s=2r
C. s=4r
D. s=r/2
28.

A. 200
B. 100
C. 50
D. 400
29.

A. true
B. false
30.

## The balance energy required for punching is supplied by the flywheel by

A. increase in its kinetic energy
B. decrease in its kinetic energy
C. decrease in its potential energy
D. by variation of mass
Answer» B. decrease in its kinetic energy
31.

A. t/s
B. t/2s
C. t/2r
D. t/r
32.

A. base circle
B. pitch circle
C. prime circle
D. pitch curve
33.

## The angle between the direction of the follower motion and a normal to the pitch curve is called

A. pitch angle
B. prime angle
C. base angle
D. pressure angle
34.

## The cam follower generally used in automobile engines is

A. knife edge follower
B. flat faced follower
C. spherical faced follower
D. roller follower
35.

## The cam follower extensively used in air- craft engines is

A. knife edge follower
B. flat faced follower
C. spherical faced follower
D. roller follower
36.

## In a radial cam, the follower moves

A. in a direction perpendicular to the cam axis
B. in a direction parallel to the cam axis
C. in any direction irrespective of the cam axis
D. along the cam axis
Answer» A. in a direction perpendicular to the cam axis
37.

## A radial follower is one

A. that reciprocates in the guides
B. that oscillates
C. in which the follower translates along an axis passing through the cam centre of rotation.
D. none of the mentioned
Answer» A. that reciprocates in the guides
38.

## Ofset is provided to a cam follower mechanism to

A. minimise the side thrust
B. accelerate
C. avoid jerk
D. none of the mentioned
Answer» A. minimise the side thrust
39.

## For low and moderate speed engines, the cam follower should move with

A. uniform velocity
B. simple harmonic motion
C. uniform acceleration and retardation
D. cycloidal motion
40.

## For high speed engines, the cam follower should move with

A. uniform velocity
B. simple harmonic motion
C. uniform acceleration and retardation
D. cycloidal motion
41.

## Which of the following displacement diagrams should be chosen for better dynamic performance of a cam-follower mechanism ?

A. simple hormonic motion
B. parabolic motion
C. cycloidal motion
D. none of the mentioned
42.

## The displacement of a flat faced follower when it has contact with the flank of a circular arc cam, is given by

A. r(1-cosθ)
B. r(1-sinθ)
C. (r-r1)(1-cosθ)
D. (r-r1)(1-sinθ)
43.

A. ω2×oq
B. ω2×oqsinθ
C. ω2×oqcosθ
D. ω2×oqtanθ
44.

## Centre of masses of the system lies on the axis of rotation.

A. 1, 2, 3 and 4
B. 1, 2, and 3 only
C. 2, 3 and 4 only
D. 1, 3 and 4 only
Answer» D. 1, 3 and 4 only
45.

## Which of the following statements is correct about the balancing of a mechanical system?

A. if it is under static balance, then there will be dynamic balance also
B. if it is under dynamic balance, then there will be static balance also
C. both static as well as dynamic balance have to be achieved separately
D. none of the mentioned
Answer» C. both static as well as dynamic balance have to be achieved separately
46.

## In a locomotive, the ratio of the connecting rod length to the crank radius is kept very large in order to

A. minimize the effect of primary forces
B. minimize the effect of secondary forces
C. have perfect balancing
D. start the locomotive conveniently
Answer» B. minimize the effect of secondary forces
47.

## Multi-cylinder engines are desirable because

A. only balancing problems are reduced
B. only flywheel size is reduced
C. both (a) and (b)
D. none of the mentioned
Answer» C. both (a) and (b)
48.

## Secondary forces in reciprocating mass on engine frame are

A. of same frequency as of primary forces
B. twice the frequency as of primary forces
C. four times the frequency as of primary forces
D. none of the mentioned
Answer» B. twice the frequency as of primary forces
49.

## Work produced by the 4-stroke engine is less because

A. one power stroke per 2 revolutions
B. one power stroke per revolution
C. one power stroke per 4 revolution
D. four power stroke per revolution
Answer» A. one power stroke per 2 revolutions
50.

## When the work is done on the gases, which of the following effect is observed on the turning moment diagram?

A. formation of negative loop
B. formation of positive loop
C. formation of an infinite loop
D. formation of no loop
Answer» A. formation of negative loop
51.

## Compression stroke results in

A. formation of negative loop
B. formation of positive loop
C. formation of an infinite loop
D. formation of no loop
Answer» A. formation of negative loop
52.

A. true
B. false
53.

## 3 BALANCING MACHINES-FIELD BALANCING OF DISCS AND ROTORS.

A. centripetal forces
B. centrifugal forces
C. friction forces
D. inertia forces
54.

A. true
B. false
55.

## Which of the following is true for centrifugal force causing unbalance?

A. direction changes with rotation
B. magnitude changes with rotation
C. direction and magnitude both change with rotation
D. direction and magnitude both remain unchanged with rotation
Answer» A. direction changes with rotation
56.

## In a revolving rotor, the centrifugal force remains balanced as long as the centre of the mass of the rotor lies

A. below the axis of shaft
B. on the axis of the shaft
C. above the axis of shaft
D. away from the axis of shaft
Answer» B. on the axis of the shaft
57.

## If the unbalanced system is not set right then.

A. static forces develop
B. dynamic forces develop
C. tangential forces develop
58.

## What is not the effect of unbalanced forces?

B. dangerous vibrations
C. stresses in various members
D. violation of conservation of mass principle
Answer» D. violation of conservation of mass principle
59.

## The critical speed of a shaft with a disc supported in between is equal to the natural frequency of the system in

A. transverse vibrations
B. torsional vibrations
C. longitudinal vibrations
D. none of the mentioned
60.

## In vibration isolation system, if ω/ωn < 2, then for all values of damping factor, the transmissibility will be

A. less than unity
B. equal to unity
C. greater than unity
D. zero
61.

## The accelerometer is used as a transducer to measure earthquake in Richter scale. Its design is based on the principle that

A. its natural frequency is very low in comparison to the frequency of vibration
B. its natural frequency is very high in comparison to the frequency of vibration
C. its natural frequency is equal to the frequency of vibration
D. measurement of vibratory motion is without any reference point
Answer» C. its natural frequency is equal to the frequency of vibration
62.

## Critical speed is expressed as

A. rotation of shaft in degrees
B. rotation of shaft in radians
C. rotation of shaft in minutes
D. natural frequency of the shaft
Answer» D. natural frequency of the shaft
63.

## The first critical speed of an automobile running on a sinusoidal road is calculated by (modeling it as a single degree of freedom system)

A. resonance
B. approximation
C. superposition
D. rayleigh quotient
64.

A. ωn
B. 0.408ωn
C. 0.204ωn
D. 0.167ωn
65.

## 6 kN/m and the damping constant of the damper is 400 Ns/m. If the mass is 50 kg, then the damping factor (d ) and damped natural frequency (fn), respectively, are

A. 0.471 and 1.19 hz
B. 0.471 and 7.48 hz
C. 0.666 and 1.35 hz
D. 0.666 and 8.50 hz
Answer» A. 0.471 and 1.19 hz
66.

A. 4.19
B. 5
C. 3.49
D. 3.36
67.

## Which of the following expression represent the angular acceleration α of the connecting rod?

A. −ω2 . sin θ/n
B. −ω2 . cos θ.n
C. ω2. cos θ/n
D. ω2 . sin θ.n
Answer» A. −ω2 . sin θ/n
68.

A. true
B. false
69.

A. 10.3
B. 11.1
C. 12.2
D. 11.8
70.

## When a body is subjected to transverse vibrations, the stress induced in a body will be

A. shear stress
B. bending stress
C. tensile stress
D. compressive stress
71.

## Longitudinal vibrations are said to occur when the particles of a body moves

A. perpendicular to its axis
B. parallel to its axis
C. in a circle about its axis
D. none of the mentioned
Answer» B. parallel to its axis
72.

## When a body is subjected to transverse vibrations, the stress induced in a body will be

A. shear stress
B. tensile stress
C. compressive stress
D. none of the mentioned
73.

## The factor which affects the critical speed of a shaft is

A. diameter of the disc
B. span of the shaft
C. eccentricity
D. all of the mentioned
Answer» D. all of the mentioned
74.

## The ratio of the maximum displacement of the forced vibration to the deflection due to the static force, is known as

A. damping factor
B. damping coefficient
C. logarithmic decrement
D. magnification factor
75.

## Which of the following systems produce a vibration in the foundation?

A. unbalanced machine
B. balanced machine
C. coupled machine
D. uncoupled machine
76.

A. true
B. false
77.

## Which of the following is a type of transmitted force to the foundation?

A. damping force
B. undamping force
C. tensile force
D. torsional force
78.

A. 0
B. 1/2
C. 1/4
D. infinity
79.

A. 180°
B. 90°
C. 450°
D. 360°
80.

## Which of the following is true regarding Ɛ>1?

A. transmitted force is greater than applied force
B. transmitted force is less than applied force
C. spring force is less than applied force
D. damping force is less than applied force
Answer» A. transmitted force is greater than applied force
81.

A. true
B. false
82.

## The height of a Watt’s governor is

A. directly proportional to speed
B. directly proportional to (speed)
C. inversely proportional to speed
D. inversely proportional to (speed)
Answer» D. inversely proportional to (speed)
83.

## A Watt’s governor can work satisfactorily at speeds from

A. 60 to 80 r.p.m
B. 80 to 100 r.p.m
C. 100 to 200 r.p.m
D. 200 to 300 r.p.m
Answer» C. 100 to 200 r.p.m
84.

## When the sleeve of a Porter governor moves downwards, the governor speed

A. increases
B. decreases
C. remains unaffected
D. first increases and then decreases
85.

A. true
B. false
86.

## A Hartnell governor is a

B. pendulum type governor
D. inertia governor
87.

A. true
B. false
88.

## Which of the following is a pendulum type governor?

A. watt’s governor
B. porter governor
C. hartnell governor
D. none of the mentioned
89.

A. 1/2 iω2
B. iω2
C. 1/2 iωωp
D. iωωp
90.

## The engine of an aeroplane rotates in clockwise direction when seen from the tail end and the aeroplane takes a turn to the left. The effect of gyroscopic couple on the aeroplane will be

A. to dip the nose and tail
B. to raise the nose and tail
C. to raise the nose and dip of the tail
D. to dip the nose and raise the tail
Answer» C. to raise the nose and dip of the tail
91.

## The steering of a ship means

A. movement of a complete ship up and down in vertical plane about transverse axis
B. turning of a complete ship in a curve towards right or left, while it moves forward
C. rolling of a complete ship side-ways
D. none of the mentioned
Answer» B. turning of a complete ship in a curve towards right or left, while it moves forward
92.

A. true
B. false
93.

A. true
B. false
94.

A. true
B. false
95.

A. 46.548 kw
B. 56.548 kw
C. 66.548 kw
D. 76.548 kw
96.

A. 2.055 m
B. 3.055 m
C. 4.055 m
D. 5.055 m
97.

A. 10.69 knm
B. 20.69 knm
C. 30.69 knm
D. 40.69 knm
98.

## In latitude 25.0 S, SA (spin axis) of a FG (free gyro) is in position S40E and horizontal. Find the tilt after 6 hours.

A. 61.16 up
B. 61.16 down
C. 51.15 up
D. none of the mentioned
99.

## The steering of a ship means

A. movement of a complete ship up and down in vertical plane about transverse axis
B. turning of a complete ship in a curve towards right r left, while it moves forward
C. rolling of a complete ship sideways
D. none of the mentioned
Answer» B. turning of a complete ship in a curve towards right r left, while it moves forward
100.

## When the pitching of a ship is upward, the effect of gyroscopic couple acting on it will be

A. to move the ship towards starboard
B. to move the ship towards port side
C. to raise the bow and lower the stern
D. to raise the stern and lower the bow
Answer» A. to move the ship towards starboard