# Multiple choice question for engineering

## Set 1

1. The acceleration of the particle moving with simple harmonic motion is inversely proportional to the displacement of the particle from the mean position.

a) True

b) False

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2. In order to double the period of a simple pendulum, the length of the string should be

a) halved

b) doubled

c) quadrupled

d) none of the mentioned

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_{p}= 2п√L/g So, if period is doubled, then length should be quadrupled

3. The equivalent length of simple pendulum depends upon the distance between the point of the suspension and the center of gravity.

a) True

b) False

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4. Which of the following statement is correct?

a) The periodic time of a particle moving with simple harmonic motion is the time taken by a particle for one complete oscillation.

b) The periodic time of a particle moving with simple harmonic motion is directly proportional to its angular velocity.

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

d) The acceleration of the particle moving with simple harmonic motion is maximum at the mean position.

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5. The periodic time of a compound pendulum is …….. when the distance between the point of suspension and the center of gravity is equal to the radius of gyration of the body about its center of gravity.

a) zero

b) minimum

c) maximum

d) none of the mentioned

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6. In a simple harmonic motion, the velocity vector with respect to displacement vector

a) is in phase

b) leads by 90^{0}

c) leads by 180^{0}

d) lags by 90^{0}

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7. The distance between the center of suspension and center of percussion is equal to the equivalent length of a simple pendulum.

a) True

b) False

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8. The center of suspension and center of percussion are not interchangeable.

a) True

b) False

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9. When the body is suspended at the point of suspension, its periodic time and frequency will be _____________ as compared to the body suspended at the point of percussion.

a) same

b) two times

c) four times

d) eight times

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10. Bifilar suspension method is used to find the

a) angular acceleration of the body

b) moment of inertia of the body

c) periodic time of the body

d) frequency of vibration of the body

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## Set 2

1. The quick return mechanism which is an inversion of 4-bar linkage is

a) Drag link mechanism

b) Whitworth quick return mechanism

c) Crank and slotted lever mechanism

d) None of the mentioned

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2. Match list I with list II

List I List II

A. Pantograph 1. Scotch yoke mechanism

B. Single slider crank 2. Double lever mechanism

C. Double slider crank chain 3. Tchebicheff’s mechanism

D. Straight line motion mechanism 4. Double crank

5. Hand pump

a) A-4,B-3,C-5,D-1

b) A-2,B-5,C-1,D-3

c) A-2,B-1,C-5,D-3

d) A-4,B-5,C-2,D-1

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3. Match list I with list II

List I List II

A. Scott-Russel 1. Intemittent mechanism motion

B. Geneva 2. Quick return mechanism motion

C. Offset slider crank 3. Simple motion harmonic mechanism

D. Scotch Yoke 4. Straight line mechanism motion

a) A-2,B-3,C-1,D-4

b) A-3,B-2,C-4,D-1

c) A-4,B-1,C-2,D-3

d) A-4,B-3,C-1,D-2

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4. 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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5. Match list I with list II

Type of joint Motion constrained

A. Revolute 1. Three

B. Cylindrical 2. Five

C. Spherical 3. Four

4. Two

5. Zero

a) A-1,B-3,C-2

b) A-5,B-4,C-3

c) A-2,B-3,C-1

d) A-4,B-5,C-3

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6. The number of binary links, number of binary joints and number of ternary joints in Peaucelliar mechanism is

a) 6,6,0

b) 8,2,4

c) 8,4,2

d) 8,8,0

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

a) 1

b) 2

c) 3

d) 4

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F = 3(L – 1) – 2P = 3(8 – 1) – 2 x 9 = 21 – 18 = 3.

8. The following list of statements is given:

1) Grashoff’s rule states that for a planar crank-rocker 4-bar mechanism, the sum of the shortest and longest link lengths cannot be less than the sum of the remaining two link lengths.

2) Inversions of a mechanism are created by fixing different links, one at a time.

3) Geneva mechanism is an intermittent motion device.

4) Grubler’s criterion assumes mobility of a planar mechanism to be one.

The number of correct statements in the above list is

a) 1

b) 2

c) 3

d) 4

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9. A mechanism has 8 links, out of which 5 are binary, 2 are ternary and 1 is quaternary. The number of instantaneous centres of rotation will be

a) 28

b) 56

c) 62

d) 66

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10. In a dynamically equivalent system, a uniformly distributed mass is divided into

a) Three point masses

b) Four point masses

c) Two point masses

d) Infinite point masses

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11. A crank and slotted lever mechanism used in a shaper has a centre distance of 300 mm between the centre of oscillation of the slotted lever and the centre of rotation of the crank. The radius of the crank is 120 mm. Find the ratio of the time of cutting to the time of return stroke.

a) 1.62

b) 1.72

c) 1.82

d) 1.92

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∠CAB = 90°−α/ 2 or α / 2 = 90° – 23.6° = 66.4° α = 2 × 66.4 = 132.8°

We know that Time of cutting stroke/ Time of return stroke = 1.72.

12. The magnitude of velocities of the points on a rigid link is directly proportional to the distances from the points to the instantaneous centre.

a) True

b) False

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13. The velocity of the instantaneous centre relative to any third rigid link will be different.

a) True

b) False

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14. When the pin connects one sliding member and the other turning member, the angular velocity of the sliding member is __________

a) 0

b) 1

c) 2

d) 3

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15. In a slider crank mechanism, the velocity of piston becomes maximum when

a) Crank and connecting rod are in line with each other

b) Crank is perpendicular to the line of stroke of the piston

c) Crank and connecting rod are mutually perpendicular

d) Crank is 120^{0} with the line of stroke

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## Set 3

1. The gears are termed as medium velocity gears, if their peripheral velocity is

a) 1–3 m / s

b) 3–15 m / s

c) 15–30 m / s

d) 30–50 m / s

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2. The size of gear is usually specified by

a) pressure angle

b) pitch circle diameter

c) circular pitch

d) diametral pitch

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3. A spur gear with pitch circle diameter D has number of teeth T. The module m is defined as

a) m = d / T

b) m = T / D

c) m = π D / T

d) m = D.T

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4. In a rack and pinion arrangement, the rack has teeth of _______________ shape.

a) square

b) trepazoidal

c) oval

d) circular

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5. The radial distance from the _______________ to the clearance circle is called working depth.

a) addendum circle

b) dedendum circle

c) pitch circle

d) none of the mentioned

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6. The product of the diametral pitch and circular pitch is equal to

a) 1

b) 1/π

c) π

d) π × No. of teeth

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_{d}=T/D = π/p

_{c}Circular pitch, p

_{c}= πD/T Therefore, p

_{d}x p

_{c}= π.

7. The backlash for spur gears depends upon

a) module

b) pitch line velocity

c) tooth profile

d) both (a) and (b)

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8. The contact ratio for gears is

a) zero

b) less than one

c) greater than one

d) none of the mentioned

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9. If the centre distance of the mating gears having involute teeth is increased, then the pressure angle

a) increases

b) decreases

c) remains unchanged

d) none of the mentioned

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10. The form factor of a spur gear tooth depends upon

a) circular pitch only

b) pressure angle only

c) number of teeth and circular pitch

d) number of teeth and the system of teeth

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11. Lewis equation in spur gears is used to find the

a) tensile stress in bending

b) shear stress

c) compressive stress in bending

d) fatigue stress

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12. The minimum number of teeth on the pinion in order to avoid interference for 20° stub system is

a) 12

b) 14

c) 18

d) 32

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13. The allowable static stress for steel gears is approximately ____________ of the ultimate tensile stress.

a) one-fourth

b) one-third

c) one-half

d) double

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_{o}) for steel gears is approximately one-third of the ultimate tensile strength (σ

_{u}) i.e. σ

_{o}= σ

_{u}/ 3.

14. Lewis equation in spur gears is applied

a) only to the pinion

b) only to the gear

c) to stronger of the pinion or gear

d) to weaker of the pinion or gear

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15. The static tooth load should be ____________ the dynamic load.

a) less than

b) greater than

c) equal to

d) none of the mentioned

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## Set 4

1. If T is the actual number of teeth on a helical gear and φ is the helix angle for the teeth, the formative number of teeth is written as

a) T sec^{3} φ

b) T sec^{2} φ

c) T/sec^{3}φ

d) T cosec φ

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^{3}φ

2. In helical gears, the distance between similar faces of adjacent teeth along a helix on the pitch cylinders normal to the teeth, is called

a) normal pitch

b) axial pitch

c) diametral pitch

d) module

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3. In helical gears, the right hand helices on one gear will mesh ____________ helices on the other gear.

a) right hand

b) left hand

c) opposite

d) none of the mentioned

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4. The helix angle for single helical gears ranges from

a) 10° to 15°

b) 15° to 20°

c) 20° to 35°

d) 35° to 50°

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5. The helix angle for double helical gears may be made up to

a) 45°

b) 60°

c) 75°

d) 90°

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6. The outside diameter of an involute gear is equal to pitch circle diameter plus

a) 2 addendum

b) 2 dedendum

c) 3.1416 module

d) 2.157 module

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7. Pick out the false statement about relationships of spur gears.

a) Pitch diameter = module x No. of teeth

b) Module = 25.4/diametral pitch

c) dedendum = 1.25 x module

d) Base pitch = module x п x sinɸ

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8. Which of the following is not the correct property of involute curve?

a) The form or shape pf an involute curve depends upon the diameter of base circle from which it is derived

b) The angular motion of two involute gear teeth rotating at a uniform rate will be uniform, irrespective of the centre distance

c) The relative rate of motion between driving and driven gears having involute tooth curves, is established by the diameters of their pitch circles

d) the pitch diameters of mating involute gears are directly proportional to the diameters of their respective base circles

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9. Which of the following gear ratio does not result in hunting tool

a) 77/20

b) 76/21

c) 75/22

d) 71/25

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10. In measuring the chordal thickness, the vertical scale of a gear tooth caliper is set to the chordal or corrected addendum to locate the caliper jaws at the pitch line.If a = addendum, t = circular thickness of tooth at pitch diameter D, then chordal thickness is equal to

a) a + t/D

b) a + t^{2}/D

c) a + t^{3}/2D

d) a + t^{2}/4D

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^{2}/4D

## Set 5

1. Lewis equation for design of involute gear tooth predicts the dynamic load capacity of a cantilever beam of uniform strength.

a) True

b) False

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2. For a pair of gears in mesh, pressure angle and module must be different to satisfy the condition of interchangeability and correct gearing.

a) True

b) False

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3. In skew bevel gears, the axes are

a) non-parallel and non-intersecting, and teeth are curved

b) non-parallel and non-intersecting, and teeth are straight

c) intersecting, and teeth are curved and oblique

d) intersecting, and teeth are curved and can be ground

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4. In case the number of teeth on two bevel gears in mesh is 30 and 60 respectively, then the pitch cone angle of the gear will be

a) tan^{-1}2

b) п/2 + tan^{-1}2

c) п/2 – tan^{-1}0.5

d) tan^{-1}0.5

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_{P}/N

_{G}N

_{P}= No. of teeth of pinion N

_{G}= No. of teeth of gear ɸ = Pitch cone angle ɸ = tan

^{-1}(30/60) ɸ = tan

^{-1}0.5.

5. Consider the following statements:

The axes of spiral bevel gear are non-parallel and intersecting.

1. The most common pressure angle for spiral bevel gear is 20^{o}.

2. The most common spiral angle for spiral bevel gear is 35^{o}.

3. Spiral bevel gears are generally interchangeable.

4. Spirals are noisy and recommended for low speeds of 10 m/s.

Which of the above statements are correct?

a) 1 and 4

b) 1 and 2

c) 2 and 3

d) 3 and 4

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^{o}, spiral gear operation is noisy hence recommended for low speed operation.

6. Consider the following statements:

In case of helical gears, teeth are cut at an angle to the axis of rotation of the gears.

1. Helix angle introduces another ratio called axial contact ratio.

2. Transverse contact ratio is equal to axial contact ratio in helical gears.

3. Large transverse contact ratio does not allow multiple teeth to share the load.

4. Large axial contact ratio will cause larger axial force component.

Which of the above statements are correct?

a) 1 and 2

b) 2 and 3

c) 1 and 4

d) 3 and 4

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7. A worm gear set is designed to have pressure angle of 30^{0} which is equal to the helix angle. The efficiency of the worm gear set at an interface friction of 0.05 is

a) 87.9%

b) 77.9%

c) 67.9%

d) 57.9%

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^{2}tanλ = -(0.05) + √1 + (0.05)

^{2}tanλ = 0.9512

ȵ = 89.1%

So most suitable option is ‘a’.

8. The use of straight or curved external gear teeth in mesh with internal teeth in gear and spline couplings is specifically employed accommodate

a) torsional misalignment

b) parallel misalignment

c) angular misalignment

d) substantial axial movements between shafts

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9. A planetary gear train is gear train having

a) a relative motion of axes and the axis of at least one of the gears also moves relative to the frame

b) no relative motion of axes and no relative motion of axes with respect to the frame

c) no relative motion of axes and the axis of at least one of the gears also moves relative to the frame

d) a relative motion of axes and none of the axes of gears has relative motion with the frame

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10. The load on a gear tooth is 50 kN. If the gear is transmitting a torque of 6000 Nm, the diameter of the gear is approximately

a) 0.5 m

b) 0.75 m

c) 1 m

d) 0.25 m