# Multiple choice question for engineering

## Set 1

1. There are two points P and Q on a planar rigid body. The relative velocity between the two points

a) should always be along PQ

b) can be oriented along any direction

c) should always be perpendicular to PQ

d) should be along QP when the body undergoes pure translation

### View Answer

_{QP}= Relative velocity between P & Q = v

_{P}− v

_{Q}always perpendicular to PQ.

2. For a four-bar linkage in toggle position, the value of mechanical advantage is

a) 0.0

b) 0.5

c) 1.0

d) ∞

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^{0}and 180

^{0}. So M.A = ∞.

3. The number of inversion for a slider crank mechanism is

a) 6

b) 5

c) 4

d) 3

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4. Match the item in columns I and II

Column I Column II

P. Addendum 1. Cam

Q. Instantaneous centre of velocity 2. Beam

R. Section modulus 3. Linkage

S. Prime circle 4. Gear

a) P-4, Q-2, R-3, S-1

b) P-4, Q-3, R-2, S-1

c) P-3, Q-2, R-1, S-4

d) P-3, Q-4, R-1, S-2

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5. Match the items in columns I and II

Column I Column II

P. Higher Kinematic Pair 1. Grubler’s Equation

Q. Lower Kinemation Pair 2. Line contact

R. Quick Return Mechanism 3. Euler’s Equation

S. Mobility of a Linkage 4. Planar

5. Shaper

6. Surface contact

a) P-2, Q-6, R-4, S-3

b) P-6, Q-2, R-4, S-1

c) P-6, Q-2, R-5, S-3

d) P-2, Q-6, R-5, S-1

### View Answer

So correct pairs are, P-2, Q-6, R-5, S-1.

6. In a four-bar linkage, S denotes the shortest link length, L is the longest link length, P and Q are the lengths of other two links. At least one of the three moving links will rotate by 360^{0} if

a) S + L < P + Q

b) S + L > P + Q

c) S + P < L + Q

d) S + P > L + Q

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7. The number of degrees of freedom of a planar linkage with 8 links and 9 simple revolute joints is

a) 1

b) 2

c) 3

d) 4

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8. The lengths of the links of a 4-bar linkage with revolute pairs are p,q,r, and s units. given that p<q<r<s. Which of these links should be the fixed one, for obtaining a “double crank” mechanism ?

a) link of length p

b) link of length q

c) link of length r

d) link of length s

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9. When a cylinder is located in a Vee-block, the number of degrees of freedom which are arrested is

a) 2

b) 4

c) 7

d) 8

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10. The minimum number of links in a single degree-of-freedom planar mechanism with both higher and lower kinematic pairs is

a) 2

b) 3

c) 4

d) 5

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11. The total number of instantaneous centres for a mechanism consisting of n links are

a) n/2

b) n

c) n – 1/2

d) n(n – 1)/2

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12. According to Aronhold Kennedy’s theorem, if three bodies move relatively to each other, their instantaneous centres will lie on a

a) straight line

b) parabolic curve

c) ellipse

d) none of the mentioned

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13. In a mechanism, the fixed instantaneous centres are those centres which

a) remain in the same place for all configurations of the mechanism

b) vary with the configuration of the mechanism

c) moves as the mechanism moves, but joints are of permanent nature

d) none of the mentioned

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14. The instantaneous centres which vary with the configuration of the mechanism, are called

a) permanent instantaneous centres

b) fixed instantaneous centres

c) neither fixed nor permanent instantaneous centres

d) none of the mentioned

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15. When a slider moves on a fixed link having curved surface, their instantaneous centre lies

a) on their point of contact

b) at the centre of curvature

c) at the centre of circle

d) at the pin joint

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## Set 2

1. Which is the false statement about the properties of instantaneous centre?

a) at the instantaneous centre of rotation, one rigid link rotates instantaneously relative to another for the configuration of mechanism considered

b) the two rigid links have no linear velocities relative to each other at the instantaneous centre

c) the two rigid links which have no linear velocity relative to each other at this centre have the same linear velocity to the third rigid link

d) the double centre can be denoted either by O_{21} or O_{12}, but proper selection should be made

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2. Instantaneous center of rotation of a link in a four bar mechanism lies on

a) right side pivot of this link

b) left side pivot of this link

c) a point obtained by intersection on extending adjoining links

d) none of the mentioned

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3. The total number of instantaneous centers for a mechanism of n links is

a) n(n – 1)/2

b) n

c) n – 1

d) n(n – 1)

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4. The number of links and instantaneous centers in a reciprocating engine mechanism are

a) 4,4

b) 4,5

c) 5,4

d) 4,6

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5. According to Kennedy’s theorem, if three bodies have plane motions, their instantaneous centres lie on

a) a triangle

b) a point

c) two lines

d) a straight line

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6. In a rigid link OA, velocity of A w.r.t. O will be

a) parallel to OA

b) perpendicular to OA

c) at 45^{0} to OA

d) along AO

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7. Two systems shall be dynamically equivalent when

a) the mass of two are same

b) c.g. of two coincides

c) M.I. of two about an axis through c.g. is equal

d) all of the mentioned

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8. A link is rotating about O. Velocity of point P on link w.r.t. point Q on link will be perpendicular to

a) OP

b) OQ

c) PQ

d) line in between OP and OQ

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9. The velocity of any point in mechanism relative to any other point on the mechanism on velocity polygon is represented by the line

a) joining the corresponding points

b) perpendicular to line

c) at 45^{0} to line

d) none of the mentioned

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10. The absolute acceleration of any point P in a link about center of rotation O is

a) along PO

b) perpendicular to PO

c) at 45^{0} to PO

d) none of the mentioned

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11. Angular acceleration of a link can be determined by dividing the

a) centripetal component of acceleration with length of link

b) tangential component of acceleration with length of link

c) resultant acceleration with length of link

d) all of the mentioned

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## Set 3

1. Gearing contact is which one of the following?

a) Sliding contact

b) Sliding contact, only rolling at pitch point

c) Rolling contact

d) Rolling and sliding at each point of contact

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2. An external gear with 60 teeth meshes with a pinion of 20 teeth, module being 6 mm. What is the centre distance in mm?

a) 120

b) 180

c) 240

d) 300

### View Answer

_{1}+ T

_{2}) = 6/2 (60 + 20) = 240 mm

3. Which one of the following is true for involute gears?

a) Interference is inherently absent

b) Variation in centre distance of shafts increases radial force

c) A convex flank is always in contact with concave flank

d) Pressure angle is constant throughout the teeth engagement

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4. In involute gears the pressure angle is

a) Dependent on the size of teeth

b) dependent on the size of gears

c) Always constant

d) always variable

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5. Consider the following statements:

1. A stub tooth has a working depth larger than that of a full-depth tooth.

2. The path of contact for involute gears is an arc of a circle.

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

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6. Consider the following statements regarding the choice of conjugate teeth for the profile of mating gears:

1. They will transmit the desired motion

2. They are difficult to manufacture.

3. Standardisation is not possible

4. The cost of production is low.

Which of these statements are correct?

a) 1, 2 and 3

b) 1, 2 and 4

c) 2, 3 and 4

d) 1, 3 and 4

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7. Common contact ratio of a pair of spur pinion and gear is

a) Less than 1·0

b) Equal to 1

c) Between 2 and 3

d) Greater than 3

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8. In gears, interference takes place when

a) The tip of a tooth of a mating gear digs into the portion between base and root circles

b) Gears do not move smoothly in the absence of lubrication

c) Pitch of the gear is not same

d) gear teeth are undercut

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9. Consider the following characteristics:

1. Small interference

2. Strong tooth.

3. Low production cost

4. Gear with small number of teeth.

Those characteristics which are applicable to stub 20° involute system would include

a) 1 alone

b) 2, 3 and 4

c) 1, 2 and 3

d) 1, 2, 3 and 4

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10. A spur gear transmits 10 kW at a pitch line velocity of 10 m/s; driving gear has a diameter of 1.0 m. Find the tangential force between the driver and the follower, and the transmitted torque respectively.

a) 1 kN and 0.5 kN-m

b) 10 kN and 5 kN-m

c) 0.5 kN and 0.25 kN-m

d) 1 kN and 1 kN-m

### View Answer

^{3}/10 = 1000 N/m Torque Transmitted = Force x diameter/2 = 1000 x 1/2 = 500 N-m = 0.5 kN-m

## Set 4

1. The periodic time (t_{p}) is given by

a) ω / 2 π

b) 2 π / ω

c) 2 π × ω

d) π/ω

### View Answer

_{p}= 2 π/ω seconds.

2. The velocity of a particle moving with simple harmonic motion is . . . . at the mean position.

a) zero

b) minimum

c) maximum

d) none of the mentioned

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_{max}= ω.r.

3. The velocity of a particle (v) moving with simple harmonic motion, at any instant is given by

a) ω √r^{2} − x^{2}

b) ω √x^{2} − r^{2}

c) ω^{2} √r^{2} − x^{2}

d) ω^{2}√x^{2} − r^{2}

### View Answer

_{N}= vsinθ = ω.rsinθ = ω √r

^{2}− x

^{2}.

4. The maximum acceleration of a particle moving with simple harmonic motion is

a) ω

b) ω.r

c) ω^{2}.r

d) ω^{2}/r

### View Answer

_{N}= ω

^{2}.rcosθ = ω

^{2}.r.

5. The frequency of oscillation for the simple pendulum is

a) 1/2π √L/g

b) 1/2π √g/L

c) 2π √L/g

d) 2π√g/L

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6. When a rigid body is suspended vertically and it oscillates with a small amplitude under the action of the force of gravity, the body is known as

a) simple pendulum

b) torsional pendulum

c) compound pendulum

d) second’s pendulum

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7. The frequency of oscillation of a compound pendulum is

a) 1/2π √g.h/k^{2}_{G} +h^{2}

b) 1/2π √k^{2}_{G} +h^{2}/g.h

c) 2π√g.h/k^{2}_{G} +h^{2}

d) 2π√k^{2}_{G} +h^{2}/g.h

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_{p}= 2π√Displacement/Accleration = 2π√θ/α and frequency of oscillation,n = 1/t

_{p}= 1/2π √g.h/k

^{2}

_{G}+h

^{2}where k

_{G}= Radius of gyration about the centroidal axis, and h = Distance between the point of suspension and centre of gravity of the body.

8. The equivalent length of a simple pendulum which gives the same frequency as the compound pendulum is

a) h/ k^{2}_{G} +h^{2}

b) k^{2}_{G} +h^{2}/h

c) h^{2}/k^{2}_{G} +h^{2}

d) k^{2}_{G} +h^{2}/h^{2}

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^{2}

_{G}+h

^{2}/h.

9. The centre of percussion is below the centre of gravity of the body and is at a distance equal to

a) h / k_{G}

b) h.k_{G}

c) h^{2}/k_{G}

d) k^{2}_{G}/h

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^{2}

_{G}/h. The distance between the centre of suspension and the centre of percussion is equal to the equivalent length of a simple pendulum.

10. The frequency of oscillation of a torsional pendulum is

a) 2πk_{G}/r √g/I

b) r/2πk_{G}√g/I

c) 2πk_{G}/r√I/g

d) r/2πk_{G}√I/g

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## Set 5

1. In a reciprocating steam engine, which of the following forms a kinematic link ?

a) cylinder and piston

b) piston rod and connecting rod

c) crank shaft and flywheel

d) flywheel and engine frame

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2. The motion of a piston in the cylinder of a steam engine is an example of

a) completely constrained motion

b) incompletely constrained motion

c) successfully constrained motion

d) none of the mentioned

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3. The motion transmitted between the teeth of gears in mesh is

a) sliding

b) rolling

c) may be rolling or sliding depending upon the shape of teeth

d) partly sliding and partly rolling

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4. The cam and follower without a spring forms a

a) lower pair

b) higher pair

c) self closed pair

d) force closed pair

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5. A ball and a socket joint forms a

a) turning pair

b) rolling pair

c) sliding pair

d) spherical pair

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6. The lead screw of a lathe with nut forms a

a) sliding pair

b) rolling pair

c) screw pair

d) turning pair

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7. When the elements of the pair are kept in contact by the action of external forces, the pair is said to be a

a) lower pair

b) higher pair

c) self closed pair

d) force closed pair

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8. Which of the following is a turning pair ?

a) Piston and cylinder of a reciprocating steam engine

b) Shaft with collars at both ends fitted in a circular hole

c) Lead screw of a lathe with nut

d) Ball and socket joint

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9. 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

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10. The relation between the number of pairs ( p ) forming a kinematic chain and the number of links (l) is

a) l = 2p – 2

b) l = 2p – 3

c) l = 2p – 4

d) l = 2p – 5