100 Common Engineering Mechanics MCQ with Answer
QNo.1
Which type of gear train is used in clock mechanism to join hour hand and
minute hand?
- A. Simple gear train
- B. Compound gear train
- C. Reverted gear train
- D. Epicyclic gear train
QNo.2 The friction experienced by a body, when
in motion, is known as
- A. Rolling friction
- B. Dynamic friction
- C. Limiting friction
- D. Static friction
QNo.3 If a ladder is not in equilibrium against
a smooth vertical wall, then it can be made in equilibrium by
- A. Increasing the angle of inclination.
- B. Decreasing the angle of inclination.
- C. Increasing the length of the ladder.
- D. Decreasing the length of the ladder.
QNo.4 The magnitude of the force of friction
between two bodies, one lying above the other, depends upon the roughness of
the
- A. Upper body
- B. Lower Body
- C. Both the bodies
- D. body having more roughness
QNo.5 Concurrent forces are those forces whose
lines of action
- A. Lie on the same line
- B. Meet at one point
- C. Meet on the same plane
- D. None of these
QNo.6 A redundant frame is also called
__________ frame.
A. Perfect
B. Imperfect
C. Deficient
D. None of these
QNo.7 Moment of inertia of a hollow circular
section (with D outer and d inner diameter), about X -axis, is
- A. π/ 16 (D² - d²)
- B. π/ 16 (D³ - d³)
-
C. π/ 32 (D⁴ - d⁴)
- D. π/ 64 (D⁴ - d⁴)
QNo.8 The angle which an inclined plane makes
with the horizontal when a body placed on it is about to move down is known as
angle of
- A. Friction
- B. Limiting friction
- C. Repose
- D. Kinematic friction
QNo.9 In which of the following type of gear
train the first gear and the last gear are co-axial.
- A. Simple gear train
- B. Compound gear train
- C. Reverted gear train
- D. Epicyclic gear train
QNo.10 Moment of inertia of a rectangular
section having width ( b ) and depth ( d ) about an axis passing through its
C.G. and parallel to the width ( b ), is
- A. db³/ 12
- B. bd³/ 12
- C. db³/ 36
- D. bd³/ 36
QNo.11 The total motion possessed by a body, is
called
- A. Impulsive force
- B. Mass
- C. Weight
- D. Momentum
QNo.12 In a simple gear train, if the
number of idle gears is odd, then the motion of driven gear will
- A. be same as that of driving gear
- B. be opposite as that of driving gear
- C. depend upon the number of teeth on the driving gear
- D. none of the mentioned
QNo.13 A fixed gear having 200 teeth is in mesh
with another gear having 50 teeth. The two gears are connected by an arm. The
number of turns made by the smaller gear for one revolution of arm about the
centre of bigger gear is
- A. 2
- B. 4
- C. 3
- D. 6
QNo.14 The length of belt used in a cross
belt drive is ..... than that used in open belt drive, provided distance
between the two pulleys and their diameters remains the same.
- A. less than
- B. equal to
- C. mare than
- D. none of the above
QNo.15 The angular velocity (in rad/s) of a
body rotating at N revolutions per minute is
- A. π N /60
- B. π N /180
- C. 2π N /60
- D. 2π N /180
QNo.16 Centre of gravity of a triangle lies on
the axis at the height
- A. One fourth of the total height above base
- B. One third of the total height above base
- C. One-half of the total height above base
- D. Three eighth of the total height above the base
QNo.17 The moment of inertia of a sphere of
mass 'm' and radius 'r', about an axis tangential to it, is
- A. 2 mr 2 /3
- B. 2 mr 2 /5
- C. 7 mr 2 /3
- D. 7 mr 2 /5
QNo.18 The product of either force of couple
with the arm of the couple is called
- A. Resultant couple
- B. Moment of the forces
- C. Resulting couple
- D. Moment of the couple
QNo.19 To connect two
parallel and coplanar shafts the following type of gearing is used
- A. Spur gear
- B. Bevel gear
- C. Spiral gear
- D. None of the mentioned
QNo.20 The coefficient of friction depends upon
- A. Nature of surfaces
- B. Area of contact
- C. Shape of the surfaces
- D. All of the above
QNo.21 In a gear train, when the axes of the
shafts, over which the gears are mounted, move relative to a fixed axis, is
called
- A. Simple gear train
- B. Compound gear train
- C. Reverted gear train
- D. Epicyclic gear train
22 On a ladder resting on smooth ground and
leaning against vertical wall, the force of friction will be
- A. Towards the wall at its upper end
- B. Away from the wall at its upper end
- C. Upwards at its upper end
- D. Downwards at its upper end
23 Moment of inertia of a triangular section of
base (b) and height (h) about an axis passing through its C.G. and parallel to
the base, is
- A. bh3 /4
- B. bh3 /8
- C. bh3 /12
- D. bh3 /36
24 The algebraic sum of moments of the forces
forming couple about any point in their plane is
- A. Equal to the moment of the couple
- B. Constant
- C. Both of above are correct
- D. Both of above are wrong
.25 The resultant of two equal
forces ‘P’ making an angle ‘θ’, is given by
- A. 2 P sinθ /2
- B. 2 P cosθ /2
- C. 2 P tanθ /2
- D. 2 P cotθ /2
QNo.26 The forces, which meet at one point
and their lines of action also lie on the same plane, are known as
- A. Coplanar concurrent forces
- B. Coplanar non-concurrent forces
- C. Non-coplanar concurrent forces
- D. Non-coplanar non-concurrent forces
QNo.27 Which gear train is used for higher
velocity ratios in a small space?
- A. Simple gear train
- B. Compound gear train
- C. Reverted gear train
- D. Epicyclic gear train
QNo.28 A body will begin to move down an
inclined plane if the angle of inclination of the plane is _________ the angle
of friction.
- A. Equal to
- B. Less than
- C. Greater than
- D. None of these
QNo.29 The resultant of the two forces ‘
P’ and ‘ Q’ is ‘R’. If ‘ Q’ is doubled, the new
resultant is perpendicular to ‘ P’ . Then
- A. P = Q
- B. Q = R
- C. Q = 2 R
- D. None of these
QNo.30 If a number of forces are acting at a
point, their resultant will be inclined at an angle ' θ ' with the horizontal,
such that
- A. tanθ = ΣH/ΣV
- B. tanθ = ΣV/ΣH
- C. tanθ = ΣV × ΣH
- D. tanθ = √ ( ΣV + ΣH )
QNo.31 If a given force (or a given system of
forces) acting on a body __________ the position of the body, but keeps it in
equilibrium, then its effect is to produce internal stress in the body.
- A. Change
- B. Does not change
- C. Changes periodically
- D. None of these
QNo.32 Which of the following is a vector
quantity?
- A. Energy
- B. Mass
- C. Momentum
- D. Angle
QNo.33 The height of gear above pitch
circle is called
- A. Addendum
- B. Dedendum
- C. crest
- D. root
QNo.34 The ratio of static friction to dynamic
friction is always
- A. Equal to one
- B. Less than one
- C. Greater than one
- D. None of these
QNo.35 If three forces acting in one plane upon
a rigid body, keep it in equilibrium, then they must either
- A. Meet in a point
- B. Be all parallel
- C. At least two of them must meet
- D. All the above are correct
QNo.36 The moment of inertia of a solid
cylinder of mass ' m' , radius ' r' and length ' l' about the
longitudinal axis or polar axis is
- A. mr 2 /2
- B. mr 2 /4
- C. mr 2 /6
- D. mr 2 /8
QNo.37 The units of moment of inertia of
an area are
- A. kg-m²
- B. m⁴
- C. kg/m²
- D. m³
QNo.38 Coefficient of friction is the
- A. Angle between normal reaction and the resultant of normal reaction and the limiting friction
- B. Ratio of limiting friction and normal reaction
- C. The friction force acting when the body is just about to move
- D. The friction force acting when the body is in motion
QNo.39 The friction experienced by a body, when
at rest, is known as
- A. Static friction
- B. Dynamic friction
- C. Limiting friction
- D. Coefficient of friction
QNo.40 One joule is equal to
- A. 0.1 N-m
- B. 1 N-m
- C. 10 N-m
- D. 100 N-m
QNo.41 In a simple gear train, if the number of
idle gears is odd, then the motion of driven gear will
- A. be opposite as that of driving gear
- B. be same as that of driving gear
- C. depend upon the number of teeth on the driving gear
- D. none of the mentioned
QNo.42 Unit of coefficient of friction is
- A. N
- B. N-m
- C. m
- D. unit less
QNo.43 The unit of force in S.I. units is
- A. kilogram
- B. Newton
- C. Watt
- D. Dyne
QNo.44 The centre of
gravity a T -section 100 mm × 150 mm × 50 mm from its bottom is
- A. 50 mm
- B. 75 mm
- C. 87.5 mm
- D. 125 mm
QNo.45 The unit of angular velocity is
- A. m/min
- B. rad/s
- C. Revolutions/min
- D. Both (B) and (C)
QNo.46 The term 'Centroid' is
- A. The Centre of area
- B. The point of suspension
- C. The point of application of the resultant of all the forces tending to cause a body to rotate about a certain axis
- D. None of the above
QNo.47 For any system of coplanar forces, the
condition of equilibrium is that the
- A. Algebraic sum of the horizontal components of all the forces should be zero
- B. Algebraic sum of the vertical components of all the forces should be zero
- C. Algebraic sum of moments of all the forces about any point should be zero
- D. All of the above
QNo.48 Which of the following circle is an
imaginary circle in the study of toothed gears
- A. Pitch circle
- B. Addendum circle
- C. Dedendum circle
- D. All of them
QNo.49 Joule is the unit of
- A. Force
- B. Work
- C. Power
- D. Velocity
QNo.50 difference between tooth space and tooth
width is called
- A. Backlash
- B. Clearance
- C. Face width
- D. Addendum
QNo.50 difference between tooth space and
tooth width is called
- A. Backlash
- B. Clearance
- C. Face width
- D. Addendum
QNo.51 Two forces are acting at an angle of
120°. The bigger force is 40 N and the resultant is perpendicular to the
smaller one. The smaller force is
- A. 20 N
- B. 40 N
- C. 120 N
- D. None of these
QNo.52 If D is diameter of pitch circle, and T
is number of teeth on the wheel then, the pitch of a toothed wheel is
- A. pi.D/T
- B. pi.T/D
- C. pi/T.D
- D. T/pi.D
QNo.53 The power transmitted by a belt depends
upon
- A. Sum of the tensions in the tight side and slack side
- B. Difference of tension in the tight side and slack side
- C. Both A and B
- D. none of the above
QNo.54 Unit of moment is
- A. Newton
- B. kg
- C. kg-m
- D. N-m
QNo.55 The centre of gravity of semicircle lies
at a distance of ......form its base measured along the vertical radius
- A. 3r/4
- B. 3/4r
- C. 4r/3
- D. 4/3r
QNo.56 The moment of inertia of a thin rod of
mass ' m' and length ' l' , about an axis through its centre of gravity
and perpendicular to its length is
- A. ml 2 /4
- B. ml 2 / 6
- C. ml 2 /8
- D. ml 2 /12
QNo.57 The type of gears used to connect two
non parallel and non intersecting shafts is
- A. spur gear
- B. bevel gear
- C. spiral gear
- D. helical
QNo.58 Moment of inertia of a circular section
about its diameter ( d ) is
- A. πd 3 /16
- B. πd 3 /32
- C. πd 4 /32
- D. πd 4 /64
QNo.59 Frictional force encountered after
commencement of motion is called
- A. Limiting friction
- B. Kinematic friction
- C. Frictional resistance
- D. Dynamic friction
QNo.60 Which of the following statement is
correct?
- A. The effect of centrifugal tension developed in a belt drive has no effect on the power transmitted by it.
- B. The power developed is maximum when 1/3 of the maximum tension is absorbed as centrifugal tension.
- C. The maximum tension in a belt drive is equal to the sum of tension in the tight side and centrifugal tension.
- D. All (a), (b) and ©
QNo.61 In determining stresses in frames by
methods of sections, the frame is divided into two parts by an imaginary
section drawn in such a way as not to cut more than
- A. Two members with unknown forces of the frame
- B. Three members with unknown forces of the frame
- C. Four members with unknown forces of the frame
- D. Three members with known forces of the frame
QNo.62 Moment of inertia of a circular section
about an axis perpendicular to the section is
- A. πd 3 / 8
- B. πd 3 / 16
- C. πd 3 /32
- D. πd 3 /64
QNo.63 Which of the following statement is
correct ?
- A. The gears are used for transmission of power.
- B. The gears are used where exact velocity ratio is required.
- C. In a single train of wheels, motion of both the driver and follower is like.
- D. All (a), (b) and (c).
QNo.64 Pick up wrong statement about friction
force for dry surfaces. Friction force is
- A. Proportional to normal load between the surfaces
- B. Dependent on the materials of contact surface
- C. Proportional to velocity of sliding
- D. Independent of the area of contact surfaces
QNo.65 Forces are called coplanar when
all of them acting on body lie in
- A. One point
- B. One plane
- C. Different planes
- D. Perpendicular planes
QNo.66 The unit of power in S.I. units is
- A. Horsepower
- B. Joule
- C. Watt
- D. kg-m
QNo.67 Moment of inertia of a rectangular
section having width ( b ) and depth ( d ) about an axis passing through its
C.G. and parallel to the depth ( d ), is
- A. db³/ 12
- B. bd³/ 12
- C. db³/ 36
- D. bd³/ 36
QNo.68 According to parallel axis theorem, the
moment of inertia of a section about an axis parallel to the axis
through center of gravity (i.e. I P ) is given by(where,
A = Area of the section, I G = Moment of inertia of the section
about an axis passing through its C.G., and h = Distance between
C.G. and the parallel axis.)
- A. I P = I G + Ah 2
- B. I P = I G - Ah 2
- C. I P = I G / Ah 2
- D. I P = Ah 2 / I G
QNo.69 A circular
hole of radius (r) is cut out from a circular disc of radius (2r) in such a way that the diagonal of
the hole is the radius of the disc. The centre of gravity of the section lies at
- A. Centre of a disc
- B. Centre of the hole
- C. Somewhere in the disc
- D. Somewhere in the hole
QNo.70 The resultant of two forces P
and Q (such that P > Q ) acting along
the same straight line, but in opposite direction, is given by
- A. P + Q
- B. P - Q
- C. P / Q
- D. Q / P
QNo.71 In epicyclic gears the axis of one of
the gear is
- A. Fixed
- B. Not fixed
- C. Stationary
- D. Parallel
QNo.72 If the gravitational acceleration at any
place is doubled, then the weight of a body will be
- A. g /2
- B. g
- C. √ 2. g
- D. 2 g
QNo.73 Which of the following statement is
correct?
- A. The effect of centrifugal tension developed in a belt drive has no effect on the power transmitted by it.
- B. The power developed is maximum when 1/3 of the maximum tension is absorbed as centrifugal tension.
- C. The maximum tension in a belt drive is equal to the sum of tension in the tight side and centrifugal tension.
- D. All (a), (b) and (c)
QNo.74 Moment of inertia of a triangular
section of base ( b ) and height ( h ) about an axis through its base, is
- A. bh 3 /4
- B. bh 3 /8
- C. bh 3 /12
- D. bh 3 /36
QNo.75 The moment of a force
- A. Is the turning effect produced by a force, on the body, on which it acts
- B. Is equal to the product of force acting on the body and the perpendicular distance of a point and the line of action of the force
- C. Is equal to twice the area of the triangle, whose base is the line representing the force and whose vertex is the point, about which the moment is taken
- D. All of the above
QNo.76 The term 'C.G.' is
- A. The centre of area
- B. The centre of mass
- C. Both A and B
- D. None of the above
QNo.77 Tension in the cable supporting a
lift is more when the lift is moving __________ with an acceleration.
- A. Upwards
- B. Downwards
- C. Horizontal
- D. None of these
QNo.78 The force of friction always acts in a
direction opposite to that
- A. In which body tends to move
- B. In which the body is moving
- C. Both A and B
- D. None of the two
QNo.79 Number of teeth on a wheel per unit of
its pitch diameter is called
- A. Module
- B. Diametral pitch
- C. Circular pitch
- D. None of the mentioned
QNo.80 In the equation of virtual work,
following force is neglected
- A. Reaction of any smooth surface with which the body is in contact
- B. Reaction of a rough surface of a body which rolls on it without slipping
- C. Reaction at a point or an axis, fixed in space, around which a body is constrained to turn
- D. All of the above
QNo.81 The forces which do not meet at one point
and their lines of action do not lie on the same plane are known as
- A. Coplanar concurrent forces
- B. Coplanar non-concurrent forces
- C. Non-coplanar concurrent forces
- D. None of these
QNo.82 Three forces acting on a rigid
body are represented in magnitude, direction and line of action by the three
sides of a triangle taken in order. The forces are equivalent to a couple whose
moment is equal to
- A. Area of the triangle
- B. Twice the area of the triangle
- C. Half the area of the triangle
- D. None of these
QNo.83 The power developed by a body acted
upon by a torque ' T' Newton meter (N - m) and revolving at ω radian/s is
given by
- A. T .ω (in watts)
- B. T .ω/60 (in watts)
- C. T .ω/75 (in kilowatts)
- D. T .ω/4500 (in kilowatts)
QNo.84 Theorem of perpendicular axis is used in
obtaining the moment of inertia of a
- A. triangular lamina
- B. square lamina
- C. circular lamina
- D. semicircular lamina
QNo.85 Coulomb friction is the friction between
- A. Bodies having relative motion
- B. Two dry surfaces
- C. Two lubricated surfaces
- D. Solids and liquids
QNo.86 The gear used to convert rotary motion
into translating motion is
- A. Worm and wheel
- B. Crown gear
- C. Rack and pinion
- D. Spiral Bevel gear
QNo.87 The moment of inertia of a
rectangular section 3 cm wide and 4 cm deep about X - X axis is
- A. 9 cm 4
- B. 12 cm 4
- C. 16 cm 4
- D. 20 cm 4
QNo.88 The power transmitted by a belt depends
upon
- A. sum of the tensions in the tight side and slack side
- B. difference of tension in the tight side and slack side
- C. Both A & B
- D. none of the above
QNo.89 A heavy ladder resting on floor and
against a vertical wall may not be in equilibrium, if
- A. The floor is smooth, the wall is rough
- B. The floor is rough, the wall is smooth
- C. The floor and wall both are smooth surfaces
- D. The floor and wall both are rough surfaces
QNo.90 The angle of inclination of the plane at
which the body begins to move down the plane, is called
- A. Angle of friction
- B. Angle of repose
- C. Angle of projection
- D. None of these