Here are 1000 MCQs on Theory of Machine (Chapterwise).
1. In which of the following mechanism the relative motions of the rigid bodies are in one plane or in parallel planes?
a) spatial mechanism
b) spherical mechanism
c) flexure mechanism
d) planar mechanism
View Answer
Explanation: In a planar mechanism, all particles describe plane curves in space and all the curves lie in a single or parallel planes. The relative motions are constrained to a single plane. Hence, the planar mechanism is a 2 – D mechanism.
2. If there are redundant constraints in the chain and it forms a statically indeterminate structure, what is the degree of freedom or the mobility of this structure?
a) More than 0
b) Less than 0
c) 1
d) 2
View Answer
Explanation: If n ≤-1, then there are redundant constraints in the chain and a statically indeterminate structure is formed. The structure is called a preloaded structure as some stress is created within the link so that it has negative mobility.
3. If the shortest link is fixed, what type of mechanism is obtained?
a) Crank rocker mechanism
b) Linkage is not planar
c) Double crank mechanism
d) Double rocker mechanism
View Answer
Explanation: When the shortest link is fixed, the links adjacent to it rotate continuously and can be described as proper cranks. Thus, this mechanism is called a double crank mechanism.
4. Which of the following mechanism is an approximately straight-line motion mechanism?
a) Hart’s mechanism
b) Watt’s mechanism
c) Scott Russell’s mechanism
d) Peaucellier mechanism
View Answer
Explanation: Watt’s consists of three links. Two of them are of equal length whereas one is shorter. Due to the rotation motion of the longer links, the center of the shorter link traces an approximate straight line. Out of the following mechanism, Watt’s mechanism is an approximately straight line mechanism whereas the rest are exact straight line mechanisms.
5. __________ mechanism is a crossed four bar chain mechanism in early steam engines to guide the piston rod in a cylinder to have an approximate straight line motion.
a) Chebychev’s
b) Watt’s
c) Peaucellier’s
d) Grasshopper
View Answer
Explanation: Watt’s mechanism is a four bar chain mechanism and was used by Watt in steam engines so as to guide the piston rod into a cylinder to have a straight line motion. Due to the rotation motion of the longer links, the centre of the shorter link traces an approximate straight line.
6. For a Whitworth quick return motion mechanism β = 110°. Find the ratio of time of cutting stroke to time of return stroke.
a) 0.42
b) 0.44
c) 2.27
d) 2.37
View Answer
Explanation: Ratio of time of cutting stroke to time of return stroke for a Whitworth quick return motion mechanism = (360-β)/ β = (360-110)/110 = 2.27.
7. Which of these is not a type of clutch?
a) Cylindrical
b) Centrifugal
c) Single disc
d) Conical
View Answer
Explanation: Single disc, conical and centrifugal are types of clutches. Clutches are used for the transmission of power in shafts and machines which are started and stopped frequently. It is also used to deliver power to the machine which are partially or fully loaded.
8. In a multi plate clutch, the formula for T is given by ______
a) n.µ.W.r1
b) n.µ.W.(r1+r2)
c) n.µ.W.R
d) n.µ.W.r2
View Answer
Explanation: In a multi plate clutch, the formula for T is given by n.µ.W.R
The formula is the same for torque in a single plate clutch. But for large amount of torque to be transmitted, multi plate clutch is used. Multi plate clutches are used in motor vehicles and machine tools.
9. In a conical clutch, the mean radius of the bearing surface is 300 mm whereas the breadth is 20 mm. Find the inner and outer radii. The semi cone angle is 30°.
a) 140 mm, 160 mm
b) 160 mm, 140 mm
c) 155 mm, 145 mm
d) 145 mm, 155 mm
View Answer
Explanation: In a conical clutch b sinα = r1 – r2
r1 – r2 = 10 and r1 + r2 = 300
r1 = 155 mm and r2 = 145 mm.
10. If the outer and inner radius of the contact surfaces are 100 mm and 75 mm respectively and the semi cone angle is 22.5°, find the value of the face width required.
a) 65.33 mm
b) 89.43 mm
c) 23.87 mm
d) 78.94 mm
View Answer
Explanation: In a conical clutch b sinα = r1 – r2
b x sin 22.5° = 100 – 75
b = 65.33 mm.
11. The smaller and generally the driving gear of a pair of mated gears is called _________
a) rack
b) pinion
c) module
d) pitch
View Answer
Explanation: Pinion is the smaller and the driving gear of a pair of mated gears. It is used in gear train drives and is usually the smaller gear. The pinion engages the larger gear or rack that helps in the turning of the wheels of the vehicle.
12. The distance measured along the circumference of the pitch circle from a point on one tooth to the same point on the adjacent tooth is called ________________
a) circular pitch
b) line of centers
c) pitch diameter
d) pitch point
View Answer
Explanation: Circular pitch is the distance measured along the circumference of the pitch circle from a point on one tooth to the same point on the adjacent tooth. So basically, it is the distance between corresponding points of consecutive gear teeth.
p = d π/ N; where, p is the circular pitch, d is the standard pitch diameter and N is the number of teeth.
13. The locus of a point on the pitch circle from the beginning to end of engagement of two mating gears is called as ___________
a) Arc of contact
b) Path of contact
c) Path of approach
d) Arc of approach
View Answer
Explanation: Arc of contact is defined as the locus of a point on the pitch circle from beginning to end of engagement of two mating gears. It is subdivided into two sections namely arc of approach and arc of recess. Arc of approach + arc of recess = arc of contact.
14. The ratio of angle of action to the pitch angle is called ___________
a) angle of recess
b) contact ratio
c) space width
d) angle of approach
View Answer
Explanation: Contact ratio is the ratio of angle of action to the pitch angle. It is also defined as the number of pairs of teeth in contact. Contact ratio = arc of contact / circular pitch.
15. The angle turned by the gear from the beginning to the end of engagement of a pair of teeth is called ______________
a) angle of action
b) angle of contact
c) angle of recess
d) angle of approach
View Answer
Explanation: Angle of action is the angle turned by the gear from the beginning to the end of engagement of a pair of teeth. Angle of action = Arc of contact / r; where r is the radius of the pinion.
16. The condition which must be fulfilled by two gear tooth profiles to maintain a constant angular velocity ratio between them is called __________________
a) path of contact
b) interference
c) arc of contact
d) law of gearing
View Answer
Explanation: Law of gearing is the condition which must be fulfilled by two gear tooth profiles to maintain a constant angular velocity ratio between them. In order to maintain this constant angular velocity, the common normal of the tooth profiles should always pass through a fixed point on the line of centres, called fixed point.
17. Velocity of sliding at the pitch point = (ωp + ωg) x _____________
a) arc of approach
b) path of contact
c) path of recess
d) 0
View Answer
Explanation: At the pitch point, there is no relative motion between the gears. Thus, the velocity of sliding is 0. Velocity of sliding at the pitch point = (ωp + ωg) x 0 = 0.
18. The distance travelled by a point on either pitch circle of the two wheels during the period of contact of a pair of teeth is called ____________________
a) angle of action
b) path of contact
c) arc of contact
d) contact ratio
View Answer
Explanation: The arc of contact is defined as the distance travelled by a point on either pitch circle of the two wheels during the period of contact of a pair of teeth. Simply, it is traced out along the pitch circle while one pair of the teeth is in contact.
19. The contact ratio is the ratio of arc of contact to the ____________
a) module
b) circular pitch
c) dedendum
d) circular pitch
View Answer
Explanation: Contact ratio is the of the arc od contact to the circular pitch. The number of teeth in contact = arc of contact / circular pitch = path of contact / (circular pitch x cos φ).
20. When large gear reductions are needed _________ gears are used.
a) bevel
b) worm
c) helical
d) spur
View Answer
Explanation: Worm gears are used where large speed reductions are needed. The horizontal portion of the gear is called as a worm and the assembly of it with the gear is known as a worm gear. Worm can easily turn a gear but a gear cannot turn a worm because of the shallow angle on the worm.
21. Which of the following is an advantage of worm gear?
a) Has high power losses and low transmission efficiency
b) Produce a lot of heat
c) Used for reducing speed and increasing torque
d) It is expensive
View Answer
Explanation: Reduction of speed and increasing the torque is an advantage of worm gear. The rest are the disadvantages of the worm gear. Worm gears are used in gate control mechanisms, hoisting machines, automobile steering mechanisms, lifts, conveyors and presses.
22. The distance by which a helix advances along the axis of the gear for one turn around is called _____________
a) lead
b) axial pitch
c) joint line
d) normal link
View Answer
Explanation: Lead is the distance by which a helix advances along the axis of the gear for one turn around. The axial pitch is equal to the lead in a single helix and the axial pitch is one half of the lead in a double helix and so on.
23. Bevel gears are equivalent to rolling ________
a) spheres
b) cubes
c) cuboids
d) cones
View Answer
Explanation: By geometry of bevel gears, it is evident that they are equivalent to rolling cones. Their pitch surface is a cone. Bevel gears exist as pairs which can be either straight or inclined at different angles.
24. Which of the gears has the highest contact ratio?
a) Worm
b) Bevel
c) Helical
d) Spur
View Answer
Explanation: Bevel gears increase the contact ratio. It avoids interference and results in stronger pinion teeth. The gear ratio can be determined from the number of teeth, pitch diameters or pitch cone angles.
25. What is the working depth of the gear and the pinion of the bevel gears?
a) 0.7 m, 2 m
b) 3 m, 0.4 m
c) 0.4 m, 3 m
d) 2 m, 0.7 m
View Answer
Explanation: The working depth of the teeth is usually 2 m which is the same as for standard spur and helical gears, but the bevel pinion is designed with the larger addendum and has 0.7 m working depth. The gear addendum varies according to the gear ratio and is 1 m for a gear ratio of 1.
26. In a centrifugal clutch, what is ω?
a) Angular acceleration of the pulley
b) Angular running speed of the pulley
c) Angular acceleration at which the engagement begins to take place
d) Angular running speed at which the engagement takes place
View Answer
Explanation: In a centrifugal clutch, ω is the angular running speed of the body. ω1 is the angular speed at which the engagement begins to take place.
27. Which of the following clutches include shoes and spider inside the rim of the pulley?
a) Cone clutch
b) Multi plate clutch
c) Single plate clutch
d) Centrifugal clutch
View Answer
Explanation: Centrifugal clutches are incorporated into motor pulleys which consist of a number of shoes on inside of the rim of the pulley. These clutches are generally incorporated into the motor pulleys. The outer surfaces of the shoe are covered with a layer of a friction material.
28. In a centrifugal clutch, what is ω?
a) Angular acceleration at which the engagement begins to take place
b) Angular running speed at which the engagement takes place
c) Angular running speed of the pulley
d) Angular acceleration of the pulley
View Answer
Explanation: In a centrifugal clutch, ω is the angular running speed of the body. ω1 is the angular speed at which the engagement begins to take place.
29. In a multi plate clutch, number of discs on the driving shaft is given by n1. True or false?
a) True
b) False
View Answer
Explanation: In a multi plate clutch, number of discs on the driving shaft is given by n1, whereas number of discs on the driven shaft is given by n2. With the help of these two variables we can find out the number of pairs of contact surfaces.
30. In a multi plate clutch, T = 150 N-m, n = 4, µ = 0.3 and R = 0.1 m. Find the axial thrust.
a) 1800
b) 1250
c) 200
d) 18
View Answer
Explanation: T = nµWR
150 = 4 x 0.3 x W x 0.1
W = 1250 N
Thus, the axial thrust = 1250 N.
Chapterwise Multiple Choice Questions on Theory of Machine
- The Geometry of Motion
- Friction Clutches
- Velocity
- Acceleration
- Spur Gears
- Helical, Worm and Bevel Gears
- Mechanism Trains
- Synthesis of Linkages
- Spatial Mechanisms
- Dynamic Forces
- Cam & Machine Dynamics
1. Theory of Machines MCQ on the Geometry of Motion
The section contains Theory of Machines multiple choice questions and answers on planar, spherical and spatial motion, mobility, kinematic inversion, grashofs law, coupler curves, straight line and quick mechanisms.
2. Theory of Machines Multiple Choice Questions on Friction Clutches
The section contains Theory of Machines questions and answers on single and multi plate clutch, conical and centrifugal clutch.
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3. Theory of Machines MCQ on Velocity
The section contains Theory of Machines MCQs on velocity instantaneous centre properties and method.
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4. Theory of Machines Multiple Choice Questions on Acceleration
The section contains Theory of Machines multiple choice questions and answers on angular acceleration of rigid body.
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5. Theory of Machines MCQ on Spur Gears
The section contains Theory of Machines questions and answers on gear terminology, contact path, sliding velocity, contact arc and ratio, minimum number of teeth and interference.
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6. Theory of Machines Multiple Choice Questions on Helical, Worm and Bevel Gears
The section contains Theory of Machines MCQs on helical gears, worm and bevel gears.
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7. Theory of Machines MCQ on Mechanism Trains
The section contains Theory of Machines multiple choice questions and answers on epicyclic gear trains.
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8. Theory of Machines Multiple Choice Questions on Synthesis of Linkages
The section contains Theory of Machines questions and answers on general slider crank.
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9. Theory of Machines MCQ on Spatial Mechanisms
The section contains Theory of Machines MCQs on double hooke joint.
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10. Theory of Machines Multiple Choice Questions on Dynamic Forces
The section contains Theory of Machines multiple choice questions and answers on superposition principle, 4-bar mechanism.
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11. Theory of Machines MCQ on Cam & Machine Dynamics
The section contains Theory of Machines questions and answers on flywheels, gyroscopic couple and governors.
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Advanced Theory of Machine Multiple Choice Questions
Wish you the best in your endeavor to learn and master Theory of Machines!