# Multiple choice question for engineering

## Set 1

1. Which of the following disciplines provides study of inertia forces arising from the combined effect of the mass and motion of the parts?

a) theory of machines

b) applied mechanics

C) kinematics

d) kinetics

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2. Which of the following disciplines provides study of relative motion between the parts of a machine?

a) theory of machines

b) applied mechanics

C) kinematics

d) kinetics

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3. Which of the following disciplines provides study of the relative motion between the parts of a machine and the forces acting on the parts?

a) theory of machines

b) applied mechanics

C) kinematics

d) kinetics

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4. 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

a) turning pair

b) rolling pair

c) sliding pair

d) spherical pair

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5. Which of the following is a lower pair?

a) ball and socket

b) piston and cylinder

c) cam and follower

d) both a and b

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6. If two moving elements have surface contact in motion, such pair is known as

a) sliding pair

b) rolling pair

c) surface pair

d) lower pair

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7. The example of lower pair is

a) shaft revolving in a bearing

b) straight line motion mechanisms

c) automobile steering gear

d) all of the mentioned

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8. Pulley in a belt drive acts as

a) cylindrical pair

b) turning pair

c) rolling pair

d) sliding pair

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9. The example of rolling pair is

a) bolt and nut

b) lead screw of a lathe

c) ball and socket joint

d) ball bearing and roller bearing

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10. Any point on a link connecting double slider crank chain will trace a

a) straight line

b) circle

c) ellipse

d) parabola

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11. The purpose of a link is to

a) transmit motion

b) guide other links

c) act as a support

d) all of the mentioned

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12. A universal joint is an example of

a) higher pair

b) lower pair

c) rolling pair

d) sliding pair

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13. Rectilinear motion of piston is converted into rotary by

a) cross head

b) slider crank

c) connecting rod

d) gudgeon pin

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## Set 2

1. A jaw clutch is essentially a

a) positive action clutch

b) cone clutch

c) friction clutch

d) disc clutch

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2. The material used for lining of friction surfaces of a clutch should have _____________ coefficient of friction.

a) low

b) high

c) medium

d) none of the mentioned

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3. The torque developed by a disc clutch is given by

a) T = 0.25 µ.W.R

b) T = 0.5 µ.W.R

c) T = 0.75 µ.W.R

d) T = µ.W.R

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4. In case of a multiple disc clutch, if n_{1} are the number of discs on the driving shaft and n_{2} are the number of the discs on the driven shaft, then the number of pairs of contact surfaces will be

a) n_{1} + n_{2}

b) n_{1} + n_{2} – 1

c) n_{1} + n_{2} + 1

d) none of the mentioned

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_{1}are the number of discs on the driving shaft and n

_{2}are the number of the discs on the driven shaft, then the number of pairs of contact surfaces will be n

_{1}+ n

_{2}– 1.

5. The cone clutches have become obsolete because of

a) small cone angles

b) exposure to dirt and dust

c) difficulty in disengaging

d) all of the mentioned

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6. The axial force (W_{e}) required for engaging a cone clutch is given by

a) W_{n} sin α

b) W_{n} (sin α + µ cos α )

c) W_{n} (sin α + 0.25 µ cos α )

d) none of the mentioned

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_{n}(sin α + 0.25 µ cos α ) where W

_{n}= Normal force acting on the contact surfaces, α = Face angle of the cone, and µ = Coefficient of friction.

7. In a centrifugal clutch, the force with which the shoe presses against the driven member is the ___________ of the centrifugal force and the spring force.

a) difference

b) sum

c) ratio

d) none of the mentioned

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8. Centrifugal clutches are designed to provide automatic and smooth engagement of load to driving member.

a) True

b) False

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9. For a power screw having square threads with lead angle of 45^{0} and coefficient of friction of 0.15 between screw and nut, the efficiency of the power screw, neglecting collar friction, is given by

a) 74%

b) 64%

c) 54%

d) 44%

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^{0}ȵ = 74% .

## Set 3

1. 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 the mentioned

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_{N}, where RN is the normal reaction.

2. In a screw jack, the effort required to lift the load W is given by

a) P = W tan (α – φ)

b) P = W tan (α + φ)

c) P = W cos (α – φ)

d) P = W cos (α + φ)

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3. The efficiency of a screw jack is given by

a) tan (α + φ)/tan α

b) tan α / tan (α + φ)

c) tan (α − φ)/ tan α

d) tan α/ tan (α − φ)

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_{0}/ P = W tanα/ W tan(α + φ) = tan α / tan (α + φ).

4. The radius of a friction circle for a shaft of radius r rotating inside a bearing is

a) r sin φ

b) r cos φ

c) r tan φ

d) r cot φ

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5. The efficiency of a screw jack is maximum, when

a) α = 45º + φ/2

b) α = 45º – φ/2

c) α = 90º + φ

d) α = 90º − φ

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6. The maximum efficiency of a screw jack is

a) 1 – sinφ/ 1 + sinφ

b) 1 + sinφ/ 1 – sinφ

c) 1 – tanφ/ 1 + tanφ

d) 1 + tanφ/ 1 – tanφ

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_{max}= sin (90º – φ + φ) – sinφ/sin (90º – φ + φ) + sinφ = sin 90º – sin φ/sin 90º + sin φ = 1 – sinφ/ 1 + sinφ.

7. The frictional torque transmitted in a flat pivot bearing, considering uniform pressure, is

a) 1/2 × μ.W. R

b) 2/3 × μ.W. R

c) 3/4 × μ.W. R

d) μ.W.R

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8. The frictional torque transmitted in a conical pivot bearing, considering uniform wear, is

a) 1/2 × μ.W. R cosec α

b) 2/3 × μ.W. R cosec α

c) 3/4 × μ.W. R cosec α

d) μ.W.R cosec α

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9. The frictional torque transmitted by a disc or plate clutch is same as that of

a) flat pivot bearing

b) flat collar bearing

c) conical pivot bearing

d) trapezoidal pivot bearing

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10. The frictional torque transmitted by a cone clutch is same as that of

a) flat pivot bearing

b) flat collar bearing

c) conical pivot bearing

d) trapezoidal pivot bearing

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11. In automobiles, Hooke’s joint is used between which of the following?

a) Clutch and gear box

b) Gear box and differential

c) Differential and wheels

d) Flywheel and clutch

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12. Which of the following statements is not correct?

a) Hooke’s joint is used to connect two rotating co-planar, non-intersecting shafts

b) Hooke’s joint is used to connect two rotating co-planar, intersecting shafts

c) Oldham’s coupling is used to connect two parallel rotating shafts

d) Hooke’s joint is used in the steering mechanism for automobiles

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13. A Hooke’s joint is used to connect two

a) coplanar and non-parallel shafts

b) non-coplanar and non-parallel shafts

c) coplanar and parallel shafts

d) non-coplanar and parallel shafts

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14. Two shafts with an included angle of 160° are connected by a Hooke’s joint. The driving shaft runs at a uniform speed of 1500 r.p.m. The driven shaft carries a flywheel of mass 12 kg and 100 mm radius of gyration. Find the maximum angular acceleration of the driven shaft.

a) 3090 rad/s^{2}

b) 4090 rad/s^{2}

c) 5090 rad/s^{2}

d) 6090 rad/s^{2}

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^{2}= 12(0.1)

^{2}= 0.12 kg – m

^{2}

Let dω_{1} / dt = Maximum angular acceleration of the driven shaft, and
θ = Angle through which the driving shaft turns.
We know that, for maximum angular acceleration of the driven shaft,

cos 2θ = 2sin^{2}α/2 – sin^{2}α = 2sin^{2}20°/2 – sin^{2}20° = 0.124
2θ = 82.9° or θ = 41.45°
and dω_{1} / dt = ω^{2}cosα sin2θsin^{2}α/(1 – cos^{2}θsin^{2}α)^{2} = 3090 rad/s^{2}.

15. The angle between the axes of two shafts connected by Hooke’s joint is 18°. Determine the angle turned through by the driving shaft when the velocity ratio is maximum.

a) 90°

b) 180°

c) 270°

d) 360°

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_{1}/ω = cosα/1 – cos

^{2}θsin

^{2}α

The velocity ratio will be maximum when cos^{2} θ is minimum, i.e. when
cos^{2} θ = 1 or when θ = 0° or 180°.

## Set 4

1. The minimum force required to slide a body of weight W on a rough horizontal plane is

a) W sinϴ

b) W cosϴ

c) W tanϴ

d) W cosecϴ

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2. 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 the mentioned

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3. A body of weight W is required to move up the rough inclined plane whose angle of inclination with the horizontal is α. The effort applied parallel to the plane is given by

a) P = W tanα

b) P = W tan (α + ɸ)

c) P = W (sinα + μ cosα)

d) P = W (cosα + μ sinα)

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4. The coefficient of friction is the ratio of the limiting friction to the normal reaction between the two bodies.

a) True

b) False

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_{N}) between the two bodies. Mathematically, μ = F/R

_{N}.

5. In a screw jack, the effort required to lift the load W is given by

a) P = W tan (α – ɸ)

b) P = W tan (α + ɸ)

c) P = W tan (ɸ – α)

d) P = W cos (α + ɸ)

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6. In a screw jack, the effort required to lower the load W is given by

a) P = W tan (α – ɸ)

b) P = W tan (α + ɸ)

c) P = W tan (ɸ – α)

d) P = W cos (α + ɸ)

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7. The frictional torque for square thread at the mean radius r while raising load W is given by

a) T = W.rtan(α – ɸ)

b) T = W.rtan(α + ɸ)

c) T = W.rtanα

d) T = W.rtanɸ

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8. Efficiency of a screw jack is given by

a) tan(α + ɸ)/tanα

b) tanα/ tan(α + ɸ)

c) tan(α – ɸ)/tanα

d) tanα/tan(α – ɸ)

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9. The load cup of a screw jack is made separate from the head of the spindle to

a) enhance the load carrying capacity of the jack

b) reduce the effort needed for lifting the working load

c) reduce the value of frictional torque required to be countered for lifting the load

d) prevent the rotation of load being lifted

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10. The efficiency of the a screw jack is maximum, when

a) α = 45^{0} + ɸ/2

b) α = 45^{0} – ɸ/2

c) α = 90^{0} + ɸ

d) α = 90^{0} – ɸ

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## Set 5

1. _____________ is the friction, experienced by a body, due to the motion of rotation as in case of foot step bearings.

a) Pivot friction

b) Solid friction

c) Dry friction

d) None of the mentioned

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2. ______________ is the friction experienced between two dry and unlubricated surfaces in contact.

a) Pivot friction

b) Solid friction

c) Boundary friction

d) None of the mentioned

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3. ______________ is the friction, experienced between the rubbing surfaces, when the surfaces have a very thin layer of lubricant.

a) Pivot friction

b) Solid friction

c) Boundary friction

d) None of the mentioned

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4. _____________ is the friction, experienced between the rubbing surfaces, when the surfaces have a thick layer of the lubricant.

a) Fluid friction

b) Solid friction

c) Boundary friction

d) None of the mentioned

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5. _____________ is a measure of the resistance offered to the sliding one layer of the lubricant over an adjacent layer.

a) Viscocity

b) Density

c) Oiliness

d) None of the mentioned

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6. The absolute viscosity of a lubricant may be defined as the force required to cause a plate of unit area to slide with unit velocity relative to a parallel plate.

a) True

b) False

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7. The lubricant which gives ______________ force of friction is said to have greater oiliness.

a) greater

b) lesser

c) similar

d) none of the mentioned

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8. When the lubricants are smeared on two different surfaces, it is found that the force of friction with one lubricant is different than that of the other.

a) True

b) False