Multiple choice question for engineering
Set 1
1. _____________ friction is the force of friction experienced by a body when it is at rest.
a) Dynamic
b) Static
c) Sliding
d) Rolling
Answer
Answer: b [Reason:] Static friction is the force of friction experienced by a body when it is at rest.
OR Static friction is the value of the limiting friction just before slipping occurs.
2. _____________ friction is the value of the limiting friction just before slipping occurs.
a) Dynamic
b) Static
c) Sliding
d) Rolling
Answer
Answer: b [Reason:] Static friction is the force of friction experienced by a body when it is at rest.
OR Static friction is the value of the limiting friction just before slipping occurs.
3. ____________friction is the force of friction experienced by a body when it is in motion.
a) Dynamic
b) Static
c) Sliding
d) Rolling
Answer
Answer: a [Reason:] Dynamic friction is the force of friction experienced by a body when it is in motion.
OR Dynamic friction is the value of frictional force after slipping has occurred.
4. _____________ friction is the value of frictional force after slipping has occurred.
a) Dynamic
b) Static
c) Sliding
d) Rolling
Answer
Answer: a [Reason:] Dynamic friction is the force of friction experienced by a body when it is in motion.
OR Dynamic friction is the value of frictional force after slipping has occurred.
5. When a body slides over another, the frictional force experienced by the body is known as ____________ friction.
a) sliding
b) rolling
c) static
d) none of the mentioned
Answer
Answer: a [Reason:] When a body slides over another, the frictional force experienced by the body is known as sliding friction.
When a body rolls over another, frictional force experienced by the body is known as rolling friction.
6. When a body rolls over another, frictional force experienced by the body is known as _______________ friction.
a) sliding
b) rolling
c) static
d) none of the mentioned
Answer
Answer: b [Reason:] When a body slides over another, the frictional force experienced by the body is known as sliding friction.
When a body rolls over another, frictional force experienced by the body is known as rolling friction.
7. Co-efficient of rolling friction is _______________ than co-efficient of sliding friction.
a) greater
b) equal to
c) lesser
d) none of the mentioned
Answer
Answer: c [Reason:] For the same pair of surfaces, co-efficient of rolling friction is lesser than co-efficient of sliding friction.
8. Co-efficient of sliding friction for rubber on concrete is
a) 0.030
b) 0.70
c) 0.18
d) 0.004
Answer
Answer: b [Reason:] Co-efficient of sliding friction for rubber on concrete is 0.70. When tires made of rubber rolls on concrete, co-efficient of rolling friction becomes 0.030.
9. Co-efficient of sliding friction for steel is
a) 0.030
b) 0.70
c) 0.18
d) 0.004
Answer
Answer: c [Reason:] Co-efficient of sliding friction for steel is 0.18. When railway wheels made of steel rolls on rails made of steel, the co-eficient of rolling friction becomes 0.004.
10. The co-efficient of dynamic friction is _______________ than static friction.
a) greater
b) equal to
c) lesser
d) none of the mentioned
Answer
Answer: c [Reason:] Since the value of F in dynamic friction is little lesser than in static friction, the ratio F/N and hence, the co-efficient of dynamic friction will also be a little lesser than static friction.
Set 2
1. 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) none of the mentioned
Answer
Answer: b [Reason:] N1 = 200
N2 = 50
Number of turns = N1/N2
= 200/50 = 4.
2. 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
Answer
Answer: b
3. The type of gears used to connect two non parallel and non intersecting shafts is
a) Spur gear
b) Helical gear
c) Bevel gear
d) Spiral gear
Answer
Answer: d [Reason:] Spiral gear is used connect two non parallel and non intersecting shafts. Spur gear is used to connect two parallel and coplanar shafts.
4. 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
Answer
Answer: a [Reason:] Spiral gear is used connect two non parallel and non intersecting shafts. Spur gear is used to connect two parallel and coplanar shafts.
5. 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) None of the mentioned
Answer
Answer: c [Reason:] When the axes of the first gear (i.e. first driver) and the last gear (i.e. last driven or follower) are co-axial, then the gear train is known as reverted gear train.
6. 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
Answer
Answer: d [Reason:] The epicyclic gear trains are useful for transmitting high velocity ratios with gears of moderate size in a comparatively lesser space. The epicyclic gear trains are used in the back gear of lathe, differential gears of the automobiles, hoists, pulley blocks, wrist watches etc.
7. 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
Answer
Answer: d [Reason:] The epicyclic gear trains are used in the back gear of lathe, differential gears of the automobiles, hoists, pulley blocks, wrist watches etc.
8. 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
Answer
Answer: c [Reason:] Rack and pinion gears are used to convert rotation into linear motion. The flat, toothed part is the rack and the gear is the pinion. A piston coaxial to the rack provides hydraulic assistance force, and an open centered rotary valve controls the assist level.
9. The circular pitch of a gear is given by
a) Πd/t
b) Πd/2t
c) 2Πd/t
d) Πd/3t
Answer
Answer: a [Reason:] The distance measured along the pitch circle from a point on one tooth to the corresponding point on an adjacent tooth is called circular pitch.
Pc = Πd/t
Where d=diameter of pitch circle
t=number of teeth.
10. 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
Answer
Answer: b
Set 3
1. The gears used for parallel shaft arrangement are
a) mitre gear
b) face gear
c) spur gears on helical gears
d) none of the mentioned
Answer
Answer: c [Reason:] Bevel gears are the gears used for intersecting shaft arrangement.
The gears used for parallel shaft arrangement are spur gears on helical gears.
2. _____________ are the gears used for intersecting shaft arrangement.
a) bevel gears
b) beveloid gears
c) mitre gears
d) none of the mentioned
Answer
Answer: a [Reason:] Bevel gears are the gears used for intersecting shaft arrangement.
The gears used for parallel shaft arrangement are spur gears on helical gears.
3. ________________ are gears used for skew arrangement.
a) spur gears on helical gears
b) helical, worm, or hypoid gears
c) mitre gears
d) none of the mentioned
Answer
Answer: b [Reason:] Helical, worm, or hypoid gears are gears used for skew arrangement.
Bevel gears are the gears used for intersecting shaft arrangement.
4. Bevel gears used for connecting intersecting shafts at 900 and having speed ratio 1 : 1 is known as
a) bevel gears
b) beveloid gears
c) mitre gears
d) none of the mentioned
Answer
Answer: c [Reason:] Bevel gears used for connecting intersecting shafts at 900 and having speed ratio 1 : 1 is known as mitre gears.
Bevel gears with basic pressure angle of 200 with long and short addendums for ratios other than 1:1 to avoid undercut pinions and to increase strength are gleason bevel gears.
5. Tapered involute gears which can couple intersecting shafts, skew shafts, and parallel shafts are known as
a) bevel gears
b) beveloid gears
c) mitre gears
d) none of the mentioned
Answer
Answer: b [Reason:] Tapered involute gears which can couple intersecting shafts, skew shafts, and parallel shafts are known as beveloid gears.
The gears used for parallel shaft arrangement are spur gears on helical gears.
6. Gears having teeth cut on the rotating face plane of the gear and mate with standard involute spur gears are known as
a) mitre gear
b) face gear
c) spur gears on helical gears
d) none of the mentioned
Answer
Answer: b [Reason:] Worm gears are used for obtaining large speed reduction between non-intersecting shafts making an angle of 900 with each other.
Gears having teeth cut on the rotating face plane of the gear and mate with standard involute spur gears are known as face gears.
7. ____________ gears are used for obtaining large speed reduction between non-intersecting shafts making an angle of 900 with each other.
a) worm gears
b) beveloid gears
c) mitre gears
d) none of the mentioned
Answer
Answer: a [Reason:] Worm gears are used for obtaining large speed reduction between non-intersecting shafts making an angle of 900 with each other.
Gears having teeth cut on the rotating face plane of the gear and mate with standard involute spur gears are known as face gears.
8. Bevels connecting shafts other than 900 are
a) worm gears
b) angular bevel gears
c) mitre gears
d) none of the mentioned
Answer
Answer: b [Reason:] Bevels connecting non-intersecting shafts are skew bevel gears.
Bevels connecting shafts other than 900 are angular bevel gears.
9. Bevels connecting non-intersecting shafts are
a) skew bevel gears
b) angular bevel gears
c) mitre gears
d) none of the mentioned
Answer
Answer: a [Reason:] Bevels connecting non-intersecting shafts are skew bevel gears.
Bevels connecting shafts other than 900 are angular bevel gears.
10. Bevel gears with basic pressure angle of 200 with long and short addendums for ratios other than 1:1 to avoid undercut pinions and to increase strength are
a) skew bevel gears
b) angular bevel gears
c) gleason bevel gears
d) none of the mentioned
Answer
Answer: c [Reason:] Bevel gears used for connecting intersecting shafts at 900 and having speed ratio 1 : 1 is known as mitre gears.
Bevel gears with basic pressure angle of 200 with long and short addendums for ratios other than 1:1 to avoid undercut pinions and to increase strength are gleason bevel gears.
Set 4
1. Scotch yoke mechanism is used to generate
a) Sine functions
b) Square roots
c) logarithms
d) inversions
Answer
Answer: a [Reason:] In Scotch Yoke mechanism, the constant rotation of the crank produces harmonic translation of the yoke. Its four binary links are:
1. Fixed link
2. Crank
3. Sliding Block
4. Yoke.
2. Which of the following are inversions of a double slider crank chain?
1. Whitworth return motion 2. Scotch Yoke
3. Oldham’s Coupling 4. Rotary engine
Select correct answer using the codes given below:
Codes:
a) 1 and 2
b) 1, 3 and 4
c) 2 and 3
d) 2, 3 and 4
Answer
Answer: c [Reason:] Double slider crank mechanism
It has four binary links, two revolute pairs, two sliding pairs. Its various types are:
1. Scotch Yoke mechanism
2. Oldhams Coupling
3. Elliptical Trammel.
3. Oldham’s coupling is used to transmit power between two parallel shafts which are slightly offset.
a) True
b) false
Answer
Answer: a [Reason:] It is used for transmitting angular velocity between two parallel but eccentric shafts.
4. In Oldham’s coupling the condition for maximum speed ratio is
a) w1cosα/W
b) w1sinα/W
c) w1/W = 1/cosα
d) w1/W = 1/sinα
Answer
Answer: c [Reason:] w1/W = cosα/1 – cos2ϴsin2α
For maximum speed ratio cos2ϴ = 1
Therefore, w1/W = 1/cosα.
5. The relative acceleration of two points which are at variable distance apart on a moving link can be determined by using the
a) three centers in line theorem
b) instantaneous centre of rotation method
c) Coriolis component of acceleration method
d) Klein’s construction
Answer
Answer: b [Reason:] The relative acceleration of two variable points on a moving link can be determined by using the instantaneous centre of rotation method.
6. What is the number of instantaneous centres of rotation for a 6-link mechanism?
a) 4
b) 6
c) 12
d) 15
Answer
Answer: d [Reason:] N = n(n – 1)/2 = 6 x (6 – 1)/2 = 15.
7. For one degree of freedom planer mechanism having links, which one of the following is the possible combination?
a) Four binary links and two ternary links
b) Four ternary links and two binary links
c) Three ternary links and three binary links
d) One ternary link and five binary links
Answer
Answer: d [Reason:] From Grubler’s criteria 1 = 3(l – 1) – 2j
or, j = 3/2l – 2 for six link
j = 3/2 x 6 – 2 = 7 1 ternary link = 2 binary link
a) j = 4 + 2 x 2 ≠ 7
b) j = 4 x 2 + 2 ≠ 7
c) j = 3 x 2 + 2 ≠ 7
d) j = 1 x 2 + 5 ≠ 7 the ans is d.
8. Inversion of a kinematic chain relative to some other links is a property of the chain and is not that of the mechanism.
a) True
b) False
Answer
Answer: a [Reason:] In a kinematic inversion relative motion does not change but absolute motion change drastically.
9. In a shaping operation, the average cutting speed is ( Stroke length S, Number of strokes per minute N, Quick return ratio R)
a) NSR
b) NSR/2
c) NS(1 + R)
d) NS(1 + R)/2
Answer
Answer: d [Reason:] Time for forward stroke + Tf
Time for return stroke = Tr
R = Tr/Tf
Therefore, time for only one cutting stroke(T) = 1/N x Tf/(Tf + Tr)
Average cutting speed = S/T = SN(Tf + Tr)/Tf = SN(1 + R).
10. Ina kinematic inversion, the relative motions between links of the mechanism change as different links are made the frame by turns.
a) True
B) False
Answer
Answer: b [Reason:] Through the process of inversion the relative motions between the various links is not changed in any manner but their absolute motions may be changed drastically.
11. An elliptical trammel is a mechanism with three prismatic pairs and one revolute pair.
a) True
B) False
Answer
Answer: b [Reason:] Elliptical trammels have two sliding pairs and two turning pairs. It is an instrument used for drawing ellipse.
Set 5
1. When the nature of contact between the element of a pair is such that it can only slide relative to the other, the pair is known as a
a) screw pair
b) spherical pair
c) turning pair
d) sliding pair
Answer
Answer: d [Reason:] When the nature of contact between the element of a pair is such that one element can turn abut the other by screw threads, the pair is known as a screw pair. When the nature of contact between the element of a pair is such that it can only slide relative to the other, the pair is known as a sliding pair.
2. When the nature of contact between the element of a pair is such that it can turn or revolve about a fixed axis, the pair is known as a rolling pair.
a) True
b) False
Answer
Answer: b [Reason:] When the nature of contact between the element of a pair is such that it can turn or revolve about a fixed axis, the pair is known as a turning pair.
3. When the nature of contact between the element of a pair is such that one element can turn abut the other by screw threads, the pair is known as a
a) screw pair
b) spherical pair
c) turning pair
d) sliding pair
Answer
Answer: a [Reason:] When the nature of contact between the element of a pair is such that one element can turn abut the other by screw threads, the pair is known as a screw pair.
4. A sliding pair has a completely constrained motion.
a) True
b) False
Answer
Answer: a [Reason:] When the nature of contact between the element of a pair is such that it can only slide relative to the other, the pair is known as a sliding pair and it has a completely constrained motion.
5. Which of the following is an example of sliding pair?
a) Piston and cylinder of a reciprocating steam engine
b) Shaft with collars at both ends fitted into a circular hole
c) Lead screw of a lathe with nut
d) Ball and a socket joint
Answer
Answer: a [Reason:] When the nature of contact between the element of a pair is such that it can only slide relative to the other, the pair is known as a sliding pair and can be found in piston and cylinder of a reciprocating steam engine.
6. The ball and socket joint is an example of screw pair.
a) True
b) False
Answer
Answer: b [Reason:] The ball and socket joint is an example of spherical pair. When the two elements of a pair are connected in such a way that one element turns or swivels about the other fixed element, the pair formed is called a spherical pair.
7. Which of the following is an open pair?
a) Ball and socket joint
b) Journal bearing
c) Lead screw and nut
d) Cam and follower
Answer
Answer: a
8. The lead screw of a lathe with nut forms a
a) rolling pair
b) sliding pair
c) screw pair
d) turning pair
Answer
Answer: c [Reason:] When the nature of contact between the element of a pair is such that one element can turn abut the other by screw threads, the pair is known as a screw pair. The lead screw of a lathe with nut is an example of screw pair.
9. 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 into a circular hole
c) Lead screw of a lathe with nut
d) Ball and a socket joint
Answer
Answer: b [Reason:] When the two elements of a pair are constrained in such a way that one can only turn or revolve about a fixed axis of another link, the pair is known as turning pair.
10. When the two elements of a pair have a surface contact when relative motion takes place and the surface of one element slides over the surface of the other, the pair formed is known as a
a) lower pair
b) higher pair
c) self-closed pair
d) force-closed pair
Answer
Answer: a [Reason:] When the two elements of a pair have surface contact when relative motion, takes place and the surface of one element slides over the surface of the other, the pair formed is known as lower pair. It will be seen that sliding pairs, turning pairs and screw pairs form lower pairs.