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All questions of Theory of Machines (TOM) for Mechanical Engineering Exam
In Watt’s Governor, h = ________.- a)Inversely proportional to speed
- b)directly proportional to speed
- c)directly proportional to (speed)2
- d)inversely proportional to (speed)2
Correct answer is option 'D'. Can you explain this answer?
In Watt’s Governor, h = ________.
a)
Inversely proportional to speed
b)
directly proportional to speed
c)
directly proportional to (speed)2
d)
inversely proportional to (speed)2
|
Lavanya Menon answered |
For Watt Governor:
i.e height is inversely proportional to (speed)2
What will be the locus of a point on a thread unwound from a cylinder?- a)Involute
- b)Helix
- c)Straight line
- d)Circle
Correct answer is option 'A'. Can you explain this answer?
What will be the locus of a point on a thread unwound from a cylinder?
a)
Involute
b)
Helix
c)
Straight line
d)
Circle
|
|
Lavanya Menon answered |
If a straight line is rolled round a circle or a polygon without slipping or sliding, points on line will trace out involutes.
Or Involute of a circle is a curve traced out by a point on a tights string unwound or wound from or on the surface of the cylinder.
For a Hartnell governor, the loads on the spring at the lowest and highest equilibrium speeds are 1150 N and 85 N, respectively. If the lift of the governor is 1.5 cm, then spring stiffness would be - a)700 N/cm
- b)710 N/cm
- c)725 N/cm
- d)690 N/cm
Correct answer is option 'B'. Can you explain this answer?
For a Hartnell governor, the loads on the spring at the lowest and highest equilibrium speeds are 1150 N and 85 N, respectively. If the lift of the governor is 1.5 cm, then spring stiffness would be
a)
700 N/cm
b)
710 N/cm
c)
725 N/cm
d)
690 N/cm
|
Avinash Sharma answered |
let S be the stiffness of the spring, h be the lift of governor, F1 and F2 are the force exerted on sleeve at lowest and highest equilibrium speed
If a more stiff spring is used in Hartnell governor, then the governor will be ________.- a)more sensitive
- b)less sensitive
- c)sensitively remains unaffected
- d)isochronous
Correct answer is option 'B'. Can you explain this answer?
If a more stiff spring is used in Hartnell governor, then the governor will be ________.
a)
more sensitive
b)
less sensitive
c)
sensitively remains unaffected
d)
isochronous
|
Abhay Kapoor answered |
A governor is said to be sensitive when it readily responds to a small change of speed.
Stiffness is inversely proportional to sensitiveness. Therefore, if stiffness is greater, the governor will be less sensitive.
Which one of the following laws is not applicable for a simple pendulum?- a)the time period does not depend on its magnitude
- b)the time period is proportional to its length
- c)the time period is proportional to square root of its length
- d)the time period is inversely proportional to square root of its acceleration due to gravity
Correct answer is option 'B'. Can you explain this answer?
Which one of the following laws is not applicable for a simple pendulum?
a)
the time period does not depend on its magnitude
b)
the time period is proportional to its length
c)
the time period is proportional to square root of its length
d)
the time period is inversely proportional to square root of its acceleration due to gravity
|
Pritam Das answered |
A simple pendulum is one which can be considered to be a point mass suspended form a string or rod of negligible mass.
The period 
So the statement the time period is proportional to its length is wrong.
A ball and socket joint is example of _______ pair.- a)Screw
- b)Spherical
- c)Turning
- d)Rolling
Correct answer is option 'B'. Can you explain this answer?
A ball and socket joint is example of _______ pair.
a)
Screw
b)
Spherical
c)
Turning
d)
Rolling
|
Pranavi Choudhury answered |
When the two elements of a pair are connected in such a way that one element (with spherical shape) turns or swivels about the other fixed element, the pair formed is called a spherical pair. The ball and socket joint, attachment of a car mirror, pen stand etc., are the examples of a spherical pair.
What is the radial distance of a tooth from the pitch circle to the top of the tooth known as?- a)Dedendum
- b)Addendum
- c)Pitch circle diameter
- d)Module
Correct answer is option 'B'. Can you explain this answer?
What is the radial distance of a tooth from the pitch circle to the top of the tooth known as?
a)
Dedendum
b)
Addendum
c)
Pitch circle diameter
d)
Module
|
Stuti Mishra answered |
Addendum: It is the radial distance of a tooth from the pitch circle to the top of the tooth.
Dedendum: It is the radial distance of a tooth from the pitch circle to the bottom of the tooth.
Pitch circle: It is an imaginary circle which by pure rolling action, would give the same motion as the actual gear.
Pitch circle diameter: It is the diameter of the pitch circle. The size of the gear is usually specified by the pitch circle diameter. It is also called as pitch diameter.
Module: It is the ratio of the pitch circle diameter in millimetres to the number of teeth.
Module, m = D / T
Gyroscopic effect is not observed in which of the following actions performed by the ships? - a)Rolling
- b)Pitching
- c)Steering
- d)All of the above
Correct answer is option 'A'. Can you explain this answer?
Gyroscopic effect is not observed in which of the following actions performed by the ships?
a)
Rolling
b)
Pitching
c)
Steering
d)
All of the above
|
|
Diya Sarkar answered |
For the effect of gyroscopic couple to occur, the axis of precession should always be perpendicular to the axis of spin. If, however, the axis of precession becomes parallel to the axis of spin, there will be no effect of the gyroscopic couple acting on the body of the ship.In case of rolling of a ship, the axis of precession (i.e. longitudinal axis) is always parallel to the axis of spin for all positions. Hence, there is no effect of the gyroscopic couple acting on the body of a ship.
Which of the following term defines the size of the cam?- a)Base circle
- b)Prime circle
- c)Pitch circle
- d)Pitch curve
Correct answer is option 'A'. Can you explain this answer?
Which of the following term defines the size of the cam?
a)
Base circle
b)
Prime circle
c)
Pitch circle
d)
Pitch curve
|
|
Prateek Mukherjee answered |
Base Circle: It is the smallest circle, drawn tangential to cam profile. The base circle decides the overall size of the cam and thus is fundamental feature.
Pitch Curve: If we hold the cam fixed and rotate the follower in a direction opposite to that of the cam, then the curve generated by the locus of the trace point is called pitch curve. For a knife edge follower, the pitch curve and the cam profile are same whereas for a roller follower, they are separated by the radius of the roller.
Pitch Point: Pitch point corresponds to the point of maximum pressure angle, and a circle drawn with its centre at the cam centre, to pass through the pitch point, is known as the pitch circle.
Prime Circle: It is the smallest circle that can be drawn from the centre of the cam and tangent to the pitch curve.
The Interference or undercutting in involute gears can be avoided by:-- a)varying the centre distance by changing pressure angle
- b)using modified involute or composite system
- c)increasing the addendum of small wheel and reducing it for the larger wheel
- d)All options are correct
Correct answer is option 'D'. Can you explain this answer?
The Interference or undercutting in involute gears can be avoided by:-
a)
varying the centre distance by changing pressure angle
b)
using modified involute or composite system
c)
increasing the addendum of small wheel and reducing it for the larger wheel
d)
All options are correct
|
Ayush Chawla answered |
Methods of elimination of Gear tooth Interference:
- Use of a larger pressure angle (having a larger pressure angle results in a smaller base circle. As a result, more of the tooth profiles become involute)
- Under-cutting of tooth (A portion of teeth below the base circle is cut off. When teeth are produced by this process, the tip of one tooth of a gear will not contact the non-involute portion of the tooth of other gear)
- Tooth stubbing (In this process a portion of the tip of the teeth is removed, thus preventing that portion of the tip of tooth in contacting the non-involute portion of the other meshing tooth).
- Increasing the number of teeth on the gear can also eliminate the chances of interference.
- Increasing slightly the center distance between the meshing gears would also eliminate interference.
- Tooth profile modification or profile shifting (Using profile shifted gears (gears with non-standard profile) can also be an option to eliminate interference. In profile shifted meshing gears, the addendum on the pinion is shorter compared with standard gears).
Coriolis acceleration component of a slider moving at 75π mm/s on a link rotating at 60 rpm will be- a)600π mm/s2
- b)300π mm/s2
- c)600π2 mm/s2
- d)300π2 mm/s2
Correct answer is option 'D'. Can you explain this answer?
Coriolis acceleration component of a slider moving at 75π mm/s on a link rotating at 60 rpm will be
a)
600π mm/s2
b)
300π mm/s2
c)
600π2 mm/s2
d)
300π2 mm/s2
|
Sandeep Sengupta answered |
When a point on one link is sliding along another rotating link, then the Coriolis component of the acceleration is to be calculated.
ac=2ωV
Angle of dwell of cam is defined as the angle- a)During which of the follower returns to its initial position
- b)Of rotation of the cam for definite displacement of the follower
- c)Through which the cam rotates during the period in which the follower remains in the highest position
- d)Moved by the cam from the instant the follower begins to rise, till it reaches its highest position
Correct answer is option 'C'. Can you explain this answer?
Angle of dwell of cam is defined as the angle
a)
During which of the follower returns to its initial position
b)
Of rotation of the cam for definite displacement of the follower
c)
Through which the cam rotates during the period in which the follower remains in the highest position
d)
Moved by the cam from the instant the follower begins to rise, till it reaches its highest position
|
|
Nilanjan Chawla answered |
Angle of Dwell: It is the angle through which the cam turns while the follower remains stationary at the highest or the lowest position.
Pick up the wrong statement. A flywheel- a)Is used to limit the inevitable fluctuation of speed during each cycle
- b)Controls the mean speed of rotation
- c)Stores up energy and gives up whenever required
- d)Regulates the speed during one cycle of a prime mover
Correct answer is option 'B'. Can you explain this answer?
Pick up the wrong statement. A flywheel
a)
Is used to limit the inevitable fluctuation of speed during each cycle
b)
Controls the mean speed of rotation
c)
Stores up energy and gives up whenever required
d)
Regulates the speed during one cycle of a prime mover
|
|
Subham Unni answered |
A flywheel controls the speed variation caused by the engine whereas governor maintains a constant speed during load variation on the engine.
Critical or whirling speed is the speed at which the shaft tends to vibrate violently in ________.- a)Transverse direction
- b)Longitudinal direction
- c)Linear direction
- d)None of these
Correct answer is option 'A'. Can you explain this answer?
Critical or whirling speed is the speed at which the shaft tends to vibrate violently in ________.
a)
Transverse direction
b)
Longitudinal direction
c)
Linear direction
d)
None of these
|
|
Partho Choudhary answered |
Whirling speed or Critical speed of a shaft is defined as the speed at which a rotating shaft will tend to vibrate violently in the transverse direction if the shaft rotates in horizontal direction. In other words, the whirling or critical speed is the speed at which resonance occurs.
The number of instantaneous centres of rotation in a slider-crank quick-return mechanism is- a)10
- b)8
- c)6
- d)4
Correct answer is option 'C'. Can you explain this answer?
The number of instantaneous centres of rotation in a slider-crank quick-return mechanism is
a)
10
b)
8
c)
6
d)
4
|
|
Kavya Mehta answered |
Crank and slotted lever quick return motion mechanism is an inversions of Single Slider Crank Chain which is a modification of the basic four bar chain.
Number of instantaneous centres:
where L is number of links.
Which of the following statement is TRUE about the contact ratio?- a)Varies directly to the length of the arc of contact
- b)Inversely proportional to the module
- c)Inversely proportional to the circular pitch
- d)All options are correct
Correct answer is option 'D'. Can you explain this answer?
Which of the following statement is TRUE about the contact ratio?
a)
Varies directly to the length of the arc of contact
b)
Inversely proportional to the module
c)
Inversely proportional to the circular pitch
d)
All options are correct
|
|
Lakshmi Datta answered |
The ratio of the length of arc of contact to the circular pitch is known as contact ratio i.e. number of pairs of teeth in contact.
What is the condition of complete balancing of reciprocating parts of an engine?- a)Primary force and couple as well as secondary force and couple polygons must close
- b)Primary and secondary couple polygons must close
- c)Primary and secondary force polygons must close
- d)Primary force and secondary couple polygons must close
Correct answer is option 'A'. Can you explain this answer?
What is the condition of complete balancing of reciprocating parts of an engine?
a)
Primary force and couple as well as secondary force and couple polygons must close
b)
Primary and secondary couple polygons must close
c)
Primary and secondary force polygons must close
d)
Primary force and secondary couple polygons must close
|
|
Keerthana Joshi answered |
Conditions of complete balancing of reciprocating parts of an engine:
- Primary forces must balance i.e., primary force polygon is enclosed.
- Primary couples must balance i.e., primary couple polygon is enclosed.
- Secondary forces must balance i.e., secondary force polygon is enclosed.
- Secondary couples must balance i.e., secondary couple polygon is enclosed.
In gears, interference takes place when _____.- a)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
Correct answer is option 'A'. Can you explain this answer?
In gears, interference takes place when _____.
a)
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
|
Anu Deshpande answered |
Due to interference, the tip of one of the gear of the pair will tend to dig into portions of the flank of the tooth of the other member of the pair.
Transmissibility is defined as- a)Ratio of force applied to the force transmitted to the foundation
- b)Ratio of force transmitted to the foundation to the input force
- c)Sum of the forces applied and the force transmitted to the foundation
- d)Difference of force applied vis-a-vis the force transmitted to the foundation
Correct answer is option 'B'. Can you explain this answer?
Transmissibility is defined as
a)
Ratio of force applied to the force transmitted to the foundation
b)
Ratio of force transmitted to the foundation to the input force
c)
Sum of the forces applied and the force transmitted to the foundation
d)
Difference of force applied vis-a-vis the force transmitted to the foundation
|
Siddharth Menon answered |
Transmissibility is defined as the ratio of force transmitted to the foundation to the input force.
Transmissibility is an important concept in mechanical engineering that helps us understand the efficiency of force transmission from a source to a foundation. It is commonly used in the analysis and design of various mechanical systems, such as vibration isolation systems, to ensure that the forces applied are effectively transmitted without unnecessary losses.
Explanation:
Transmissibility is defined as the ratio of the force transmitted to the foundation to the input force. In other words, it quantifies how much force is actually transmitted to the foundation compared to the force applied to the system.
To better understand this concept, let's consider a simple example of a vibration isolation system. In such a system, the input force may be generated by a vibrating machine, and the goal is to minimize the transmission of vibrations to the foundation or surrounding structures.
When the input force is applied to the system, some of it gets transmitted to the foundation, and the rest may be dissipated or absorbed by the system itself. The transmissibility of the system tells us how efficient it is in transmitting the force to the foundation.
Mathematically, transmissibility is expressed as:
Transmissibility = Force Transmitted to Foundation / Input Force
For example, let's say we have an input force of 1000 N applied to a vibration isolation system. After analyzing the system, we find that only 800 N of force is transmitted to the foundation. In this case, the transmissibility would be 800 N / 1000 N = 0.8.
A transmissibility value of less than 1 indicates that there is some loss or attenuation of force during transmission. This loss can be due to various factors such as damping, flexibility, or resonance within the system. On the other hand, a transmissibility value of 1 would mean that all of the input force is effectively transmitted to the foundation.
Importance of Transmissibility:
Transmissibility is an important parameter in mechanical engineering because it helps in designing and optimizing systems for efficient force transmission. By understanding the transmissibility of a system, engineers can make informed decisions about the design parameters such as stiffness, damping, or isolation elements to achieve the desired level of force transmission.
In practical applications, such as isolating vibrations from sensitive equipment or reducing the impact of seismic forces on structures, it is crucial to have a low transmissibility value. This ensures that the majority of the force is effectively transmitted to the foundation, minimizing the potential damage or disruption caused by vibrations or external forces.
In conclusion, transmissibility is defined as the ratio of force transmitted to the foundation to the input force. It is an important concept in mechanical engineering that helps in designing and optimizing systems for efficient force transmission. By understanding and analyzing the transmissibility of a system, engineers can make informed decisions to achieve desired levels of force transmission and minimize potential damage or disruption.
Transmissibility is an important concept in mechanical engineering that helps us understand the efficiency of force transmission from a source to a foundation. It is commonly used in the analysis and design of various mechanical systems, such as vibration isolation systems, to ensure that the forces applied are effectively transmitted without unnecessary losses.
Explanation:
Transmissibility is defined as the ratio of the force transmitted to the foundation to the input force. In other words, it quantifies how much force is actually transmitted to the foundation compared to the force applied to the system.
To better understand this concept, let's consider a simple example of a vibration isolation system. In such a system, the input force may be generated by a vibrating machine, and the goal is to minimize the transmission of vibrations to the foundation or surrounding structures.
When the input force is applied to the system, some of it gets transmitted to the foundation, and the rest may be dissipated or absorbed by the system itself. The transmissibility of the system tells us how efficient it is in transmitting the force to the foundation.
Mathematically, transmissibility is expressed as:
Transmissibility = Force Transmitted to Foundation / Input Force
For example, let's say we have an input force of 1000 N applied to a vibration isolation system. After analyzing the system, we find that only 800 N of force is transmitted to the foundation. In this case, the transmissibility would be 800 N / 1000 N = 0.8.
A transmissibility value of less than 1 indicates that there is some loss or attenuation of force during transmission. This loss can be due to various factors such as damping, flexibility, or resonance within the system. On the other hand, a transmissibility value of 1 would mean that all of the input force is effectively transmitted to the foundation.
Importance of Transmissibility:
Transmissibility is an important parameter in mechanical engineering because it helps in designing and optimizing systems for efficient force transmission. By understanding the transmissibility of a system, engineers can make informed decisions about the design parameters such as stiffness, damping, or isolation elements to achieve the desired level of force transmission.
In practical applications, such as isolating vibrations from sensitive equipment or reducing the impact of seismic forces on structures, it is crucial to have a low transmissibility value. This ensures that the majority of the force is effectively transmitted to the foundation, minimizing the potential damage or disruption caused by vibrations or external forces.
In conclusion, transmissibility is defined as the ratio of force transmitted to the foundation to the input force. It is an important concept in mechanical engineering that helps in designing and optimizing systems for efficient force transmission. By understanding and analyzing the transmissibility of a system, engineers can make informed decisions to achieve desired levels of force transmission and minimize potential damage or disruption.
________ mechanism produces mathematically an exact straight line motion.- a)Ackermann
- b)Peaucellier‘s
- c)Watt
- d)None of these
Correct answer is option 'B'. Can you explain this answer?
________ mechanism produces mathematically an exact straight line motion.
a)
Ackermann
b)
Peaucellier‘s
c)
Watt
d)
None of these
|
Stuti Bajaj answered |
Peaucellier's mechanism for straight line motion
Peaucellier's mechanism, also known as the Peaucellier–Lipkin linkage, is a mechanical linkage that transforms circular motion into perfect straight-line motion. It was invented by the French engineer Charles-Nicolas Peaucellier in 1864.
Principle of Peaucellier's mechanism
- The mechanism consists of a six-bar linkage where one of the bars is allowed to rotate about a fixed point.
- When one of the other bars is connected to a point on this rotating bar, the end point of the connected bar traces out a perfect straight line.
- This straight line is a result of the complex geometric properties of the linkage and is mathematically proven to be an exact straight line.
Advantages of Peaucellier's mechanism
- The main advantage of Peaucellier's mechanism is its ability to produce straight-line motion with high precision and accuracy.
- This mechanism is widely used in various applications where precise straight-line motion is required, such as in mechanical drawing instruments and parallel motion systems.
Comparison with other mechanisms
- While other mechanisms like the Ackermann mechanism can also produce straight-line motion, Peaucellier's mechanism is unique in its mathematical precision and exact straight-line motion.
- The Watt mechanism, on the other hand, is more commonly used for converting rotary motion into reciprocating motion.
In conclusion, Peaucellier's mechanism stands out as a precise and mathematically exact mechanism for producing straight-line motion, making it a valuable tool in various engineering applications.
Peaucellier's mechanism, also known as the Peaucellier–Lipkin linkage, is a mechanical linkage that transforms circular motion into perfect straight-line motion. It was invented by the French engineer Charles-Nicolas Peaucellier in 1864.
Principle of Peaucellier's mechanism
- The mechanism consists of a six-bar linkage where one of the bars is allowed to rotate about a fixed point.
- When one of the other bars is connected to a point on this rotating bar, the end point of the connected bar traces out a perfect straight line.
- This straight line is a result of the complex geometric properties of the linkage and is mathematically proven to be an exact straight line.
Advantages of Peaucellier's mechanism
- The main advantage of Peaucellier's mechanism is its ability to produce straight-line motion with high precision and accuracy.
- This mechanism is widely used in various applications where precise straight-line motion is required, such as in mechanical drawing instruments and parallel motion systems.
Comparison with other mechanisms
- While other mechanisms like the Ackermann mechanism can also produce straight-line motion, Peaucellier's mechanism is unique in its mathematical precision and exact straight-line motion.
- The Watt mechanism, on the other hand, is more commonly used for converting rotary motion into reciprocating motion.
In conclusion, Peaucellier's mechanism stands out as a precise and mathematically exact mechanism for producing straight-line motion, making it a valuable tool in various engineering applications.
Governor is stable, when the:- a)Radius of rotation of balls increases as the equilibrium speed decreases
- b)Radius of rotation of balls increases as the equilibrium speed increased
- c)Radius of rotation of balls decreases as the equilibrium speed increases
- d)None of these
Correct answer is option 'B'. Can you explain this answer?
Governor is stable, when the:
a)
Radius of rotation of balls increases as the equilibrium speed decreases
b)
Radius of rotation of balls increases as the equilibrium speed increased
c)
Radius of rotation of balls decreases as the equilibrium speed increases
d)
None of these
|
Akshara Rane answered |
A governor is said to be stable when for every speed within the working range there is a definite configuration i.e. there is only one radius of rotation of the governor balls at which the governor is in equilibrium. For a stable governor, if the equilibrium speed increases, the radius of governor balls must also increase. A governor is said to be unstable, if the radius of rotation decreases as the speed increases.
The graph of turning moment diagram is drawn between ________.- a)crank angle and crank radius
- b)crank angle and crank effort
- c)crank effort and crank angle
- d)crank radius and crank angle
Correct answer is option 'C'. Can you explain this answer?
The graph of turning moment diagram is drawn between ________.
a)
crank angle and crank radius
b)
crank angle and crank effort
c)
crank effort and crank angle
d)
crank radius and crank angle
|
Sarita Yadav answered |
The turning moment diagram also known as crank effort diagram.
- It is the graphical representation of the turning moment or torque or crank effort (X-axis) for various position of crank (Y-axis).
- The area under the turning moment diagram gives the work done per cycle.
- The work done per cycle when divided by the crank angle per cycle gives mean torque Tm.
A cam in which the follower reciprocates or oscillates in a plane parallel to the axis of the cam is known as- a)Cylindrical Cam
- b)Circular cam
- c)Reciprocating cam
- d)Tangent cam
Correct answer is option 'A'. Can you explain this answer?
A cam in which the follower reciprocates or oscillates in a plane parallel to the axis of the cam is known as
a)
Cylindrical Cam
b)
Circular cam
c)
Reciprocating cam
d)
Tangent cam
|
|
Athul Kumar answered |
Cylindrical Cam
A cylindrical cam is a type of cam mechanism in which the follower reciprocates or oscillates in a plane parallel to the axis of the cam. It consists of a cylindrical-shaped cam with a follower that moves in a straight line or oscillates back and forth within the same plane. This type of cam is commonly used in various mechanical systems and machines.
Working Principle
The working principle of a cylindrical cam involves the rotation of the camshaft, which causes the follower to move in a linear or oscillating motion. The shape of the cam profile determines the type of motion generated by the follower. The follower is in contact with the cam surface, and as the cam rotates, it imparts a motion to the follower.
Advantages
- Simple design: Cylindrical cams have a relatively simple design compared to other types of cams, making them easy to manufacture and maintain.
- Parallel motion: The follower in a cylindrical cam reciprocates or oscillates in a plane parallel to the axis of the cam, which is beneficial in certain applications where this type of motion is required.
- Compact size: Cylindrical cams can be designed with a compact size, making them suitable for applications with limited space.
Applications
Cylindrical cams are widely used in various mechanical systems and machines, including:
- Printing presses: Cylindrical cams are used in printing presses to control the movement of the printing plate and paper feed mechanism.
- Machine tools: Cylindrical cams are used in machine tools to control the movement of the cutting tool or workpiece.
- Packaging machinery: Cylindrical cams are used in packaging machinery to control the movement of the packaging material and sealing mechanisms.
- Textile machinery: Cylindrical cams are used in textile machinery to control the movement of the yarn or fabric during weaving or knitting operations.
In conclusion, a cylindrical cam is a type of cam mechanism in which the follower reciprocates or oscillates in a plane parallel to the axis of the cam. It offers advantages such as a simple design, parallel motion, and compact size. It finds applications in various industries, including printing, machine tools, packaging, and textiles.
A cylindrical cam is a type of cam mechanism in which the follower reciprocates or oscillates in a plane parallel to the axis of the cam. It consists of a cylindrical-shaped cam with a follower that moves in a straight line or oscillates back and forth within the same plane. This type of cam is commonly used in various mechanical systems and machines.
Working Principle
The working principle of a cylindrical cam involves the rotation of the camshaft, which causes the follower to move in a linear or oscillating motion. The shape of the cam profile determines the type of motion generated by the follower. The follower is in contact with the cam surface, and as the cam rotates, it imparts a motion to the follower.
Advantages
- Simple design: Cylindrical cams have a relatively simple design compared to other types of cams, making them easy to manufacture and maintain.
- Parallel motion: The follower in a cylindrical cam reciprocates or oscillates in a plane parallel to the axis of the cam, which is beneficial in certain applications where this type of motion is required.
- Compact size: Cylindrical cams can be designed with a compact size, making them suitable for applications with limited space.
Applications
Cylindrical cams are widely used in various mechanical systems and machines, including:
- Printing presses: Cylindrical cams are used in printing presses to control the movement of the printing plate and paper feed mechanism.
- Machine tools: Cylindrical cams are used in machine tools to control the movement of the cutting tool or workpiece.
- Packaging machinery: Cylindrical cams are used in packaging machinery to control the movement of the packaging material and sealing mechanisms.
- Textile machinery: Cylindrical cams are used in textile machinery to control the movement of the yarn or fabric during weaving or knitting operations.
In conclusion, a cylindrical cam is a type of cam mechanism in which the follower reciprocates or oscillates in a plane parallel to the axis of the cam. It offers advantages such as a simple design, parallel motion, and compact size. It finds applications in various industries, including printing, machine tools, packaging, and textiles.
A gear set consists of a 16-tooth pinion driving a 40-tooth gear. The module is 12 mm. The addendum and dedendum are 12 mm and 15 mm, respectively and the gears are cut using 20° pressure angle. The centre distance is- a)36 mm
- b)136 mm
- c)236 mm
- d)336 mm
Correct answer is option 'D'. Can you explain this answer?
A gear set consists of a 16-tooth pinion driving a 40-tooth gear. The module is 12 mm. The addendum and dedendum are 12 mm and 15 mm, respectively and the gears are cut using 20° pressure angle. The centre distance is
a)
36 mm
b)
136 mm
c)
236 mm
d)
336 mm
|
|
Sanskriti Basu answered |
TP = 16, TG = 40, m = 12
C = rP + rG
336 mm
The mass of flywheel of a steam engine is 3250 kg with the radius of gyration of 1 m. The starting torque of the engine is 4500 N - m. What is the angular acceleration (rad/s2) of the flywheel?- a)3.4
- b)2
- c)2.48
- d)1.38
Correct answer is option 'D'. Can you explain this answer?
The mass of flywheel of a steam engine is 3250 kg with the radius of gyration of 1 m. The starting torque of the engine is 4500 N - m. What is the angular acceleration (rad/s2) of the flywheel?
a)
3.4
b)
2
c)
2.48
d)
1.38
|
|
Anu Deshpande answered |
Mass moment of inertia of the flywheel:
I = mk2 = 3250 × 12 = 3250 kg-m2
Starting torque of the engine: T = I.α
Angular acceleration of the flywheel:
α = T/I = 4500/3250 = 18/13 = 1.38 rad/s2
In case of cam, the maximum value of the pressure angle is kept as-- a)15°
- b)20°
- c)30°
- d)60°
Correct answer is option 'C'. Can you explain this answer?
In case of cam, the maximum value of the pressure angle is kept as-
a)
15°
b)
20°
c)
30°
d)
60°
|
|
Anand Kumar answered |
Pressure Angle is the measure of steepness of the cam profile. The angle between the direction of the follower movement and the normal to the pitch curve at any point is called pressure angle. Pressure angle varies from maximum to minimum during complete rotation.
The pressure should not exceed 30० in case of cams with translating followers (and angle should be less than 45० for low speed cam mechanisms with oscillating followers).
Which of the following mechanisms are examples of force closed kinematic Pairs?A. Cam and roller mechanismB. Door-closing mechanismC. Slider-crank mechanism- a)A and B only
- b)A and C only
- c)B and C only
- d)A, B and C
Correct answer is option 'A'. Can you explain this answer?
Which of the following mechanisms are examples of force closed kinematic Pairs?
A. Cam and roller mechanism
B. Door-closing mechanism
C. Slider-crank mechanism
a)
A and B only
b)
A and C only
c)
B and C only
d)
A, B and C
|
Nishanth Basu answered |
Self-closed pair:
When the two elements of a pair are connected together mechanically. The contact between the two can be broken only by destruction of at least one of the members.
All lower pairs and some higher pairs are closed pairs. Sliding pairs, turning pairs, spherical pairs and screw pairs are also closed pairs.
Forced-closed pair:
When two links of a pair are in contact either due to force of gravity or some spring action. In this, the links are not held together mechanically e.g. cam and follower pair (because spring is used to keep the motion constrained).
Slider-crank mechanism does not require such force.
________ gear train is used to connect minute hand to hour hand, in a clock mechanism.- a)Simple
- b)Reverted
- c)Epicyclic
- d)Compound
Correct answer is option 'B'. Can you explain this answer?
________ gear train is used to connect minute hand to hour hand, in a clock mechanism.
a)
Simple
b)
Reverted
c)
Epicyclic
d)
Compound
|
|
Dhruv Dasgupta answered |
Reverted Gear Train in Clock Mechanism
A clock mechanism consists of various gears that are interlinked to perform the function of displaying time accurately. One of the important gear trains used in a clock mechanism is the reverted gear train. Let's understand what it is and how it is used in a clock mechanism.
What is a Reverted Gear Train?
A reverted gear train is a type of gear train that consists of three gears - two idler gears and one driver gear. The driver gear and the idler gears are mounted on the same shaft, and the other end of each idler gear meshes with an output gear. The direction of rotation of the output gear is opposite to that of the driver gear.
How is it Used in a Clock Mechanism?
In a clock mechanism, the reverted gear train is used to connect the minute hand to the hour hand. The minute hand is mounted on the output gear of the reverted gear train, while the hour hand is mounted on the driver gear. As the hour hand rotates, it drives the driver gear of the reverted gear train. The two idler gears mounted on the same shaft as the driver gear, mesh with the output gear. As a result, the output gear rotates in the opposite direction to that of the driver gear. The minute hand mounted on the output gear rotates at a slower speed than the hour hand, thus indicating the minutes that have passed since the last hour.
Advantages of Reverted Gear Train in Clock Mechanism
- Provides a simple and reliable way to connect the minute hand to the hour hand
- Reduces the number of gears required in the clock mechanism
- Increases the accuracy of time display by eliminating errors due to backlash and friction
Conclusion
The reverted gear train is an important gear train used in a clock mechanism to connect the minute hand to the hour hand. It provides a simple and reliable way to display time accurately and efficiently.
A clock mechanism consists of various gears that are interlinked to perform the function of displaying time accurately. One of the important gear trains used in a clock mechanism is the reverted gear train. Let's understand what it is and how it is used in a clock mechanism.
What is a Reverted Gear Train?
A reverted gear train is a type of gear train that consists of three gears - two idler gears and one driver gear. The driver gear and the idler gears are mounted on the same shaft, and the other end of each idler gear meshes with an output gear. The direction of rotation of the output gear is opposite to that of the driver gear.
How is it Used in a Clock Mechanism?
In a clock mechanism, the reverted gear train is used to connect the minute hand to the hour hand. The minute hand is mounted on the output gear of the reverted gear train, while the hour hand is mounted on the driver gear. As the hour hand rotates, it drives the driver gear of the reverted gear train. The two idler gears mounted on the same shaft as the driver gear, mesh with the output gear. As a result, the output gear rotates in the opposite direction to that of the driver gear. The minute hand mounted on the output gear rotates at a slower speed than the hour hand, thus indicating the minutes that have passed since the last hour.
Advantages of Reverted Gear Train in Clock Mechanism
- Provides a simple and reliable way to connect the minute hand to the hour hand
- Reduces the number of gears required in the clock mechanism
- Increases the accuracy of time display by eliminating errors due to backlash and friction
Conclusion
The reverted gear train is an important gear train used in a clock mechanism to connect the minute hand to the hour hand. It provides a simple and reliable way to display time accurately and efficiently.
For a vibrating system, if the damping factor is unity, then the system is ________ damped.- a)Under
- b)Over
- c)Critically
- d)Zero
Correct answer is option 'C'. Can you explain this answer?
For a vibrating system, if the damping factor is unity, then the system is ________ damped.
a)
Under
b)
Over
c)
Critically
d)
Zero
|
|
Asha Basu answered |
The damping ratio (ζ = c/cc) is a system parameter, that can vary from un-damped (ζ = 0), under-damped (ζ < 1) through critically damped (ζ = 1) to over-damped (ζ > 1)
When one of the links of a kinematic chain is fixed, then the chain is called _______.- a)Machine
- b)Mechanism
- c)Structure
- d)Inversion
Correct answer is option 'B'. Can you explain this answer?
When one of the links of a kinematic chain is fixed, then the chain is called _______.
a)
Machine
b)
Mechanism
c)
Structure
d)
Inversion
|
|
Sanskriti Chakraborty answered |
When one of the links of a kinematic chain is fixed, the chain is known as mechanism. It may be used for transmitting or transforming motion. A mechanism with four links is known as simple mechanism, and the mechanism with more than four links is known as compound mechanism. Simplest possible mechanism is four bar chains consisting of four links, each of them forms a turning pair.
The kinetic energy of a flywheel, having moment of inertia I and angular speed ‘ω’, is given by- a)Iω
- b)Iω2
- c)
- d)None of these
Correct answer is option 'C'. Can you explain this answer?
The kinetic energy of a flywheel, having moment of inertia I and angular speed ‘ω’, is given by
a)
Iω
b)
Iω2
c)
d)
None of these
|
Hiral Jain answered |
Kinetic energy of the flywheel is given by:
I is mass moment of inertia of the flywheel about its axis of rotation in kg-m2 = m.k2
Elliptical gear train used in differential gear of automobile helps in:- a)Reducing jerk
- b)Assisting in speed change
- c)Reducing speed
- d)Turning
Correct answer is option 'D'. Can you explain this answer?
Elliptical gear train used in differential gear of automobile helps in:
a)
Reducing jerk
b)
Assisting in speed change
c)
Reducing speed
d)
Turning
|
|
Priyanka Tiwari answered |
When a vehicle takes a turn, its other rear wheel covers a greater distance than inner rear wheel. Hence differential gears are used so that both the rear wheel can rotate at different speed. This is achieved with the help of elliptical gear train.
A cantilever beam of cross section area ‘A’, moment of Inertia I and length ‘L’ is having natural frequency ω1. If the beam is accidentally broken into two halves, the natural frequency of the remaining cantilever beam ω2will be such that - a)ω2 < ω1
- b)ω2 > ω1
- c)ω2 = ω1
- d)Cannot be obtained from the given data
Correct answer is option 'B'. Can you explain this answer?
A cantilever beam of cross section area ‘A’, moment of Inertia I and length ‘L’ is having natural frequency ω1. If the beam is accidentally broken into two halves, the natural frequency of the remaining cantilever beam ω2will be such that
a)
ω2 < ω1
b)
ω2 > ω1
c)
ω2 = ω1
d)
Cannot be obtained from the given data
|
|
Anisha Chakraborty answered |
For cantilever beam
A very soft whisper may have noise level of- a)About 10 db
- b)About 30 db
- c)About 40 db
- d)About 100 db
Correct answer is option 'B'. Can you explain this answer?
A very soft whisper may have noise level of
a)
About 10 db
b)
About 30 db
c)
About 40 db
d)
About 100 db
|
|
Sai Reddy answered |
Some examples of different sound intensities as expressed in dB:
- 180 dB: Rocket at take-off
- 140 dB: Jet engine at take-off
- 120 dB: Rock band
- 110 dB: Loud thunder
- 90 dB: City traffic
- 80 dB: Loud radio
- 60 dB: Ordinary conversation
- 30 dB: Soft whisper
- 0 dB: Softest sound a person can hear
Rack and pinion arrangement is used for:- a)Linear motion to rotary motion
- b)Rotary motion to rotary motion
- c)Linear to linear motion
- d)Rotary to linear motion
Correct answer is option 'D'. Can you explain this answer?
Rack and pinion arrangement is used for:
a)
Linear motion to rotary motion
b)
Rotary motion to rotary motion
c)
Linear to linear motion
d)
Rotary to linear motion
|
|
Prerna Kaur answered |
Rack and pinion gears are used to convert rotation into linear motion. The ‘pinion’ is the normal round gear and the ‘rack’ is straight or flat.
A perfect example of this is the steering system on many cars.
The given kinematic link is
- a)Singular link
- b)Binary link
- c)Ternary link
- d)Quaternary link
Correct answer is option 'C'. Can you explain this answer?
The given kinematic link is
a)
Singular link
b)
Binary link
c)
Ternary link
d)
Quaternary link
|
|
Pallabi Tiwari answered |
A link is defined as a member or a combination of members of a mechanism, connecting other members and having motion relative to them. Thus, a link may consist of one or more resistant bodies.
Links can be classified into binary, ternary and quaternary depending upon their ends.
If C1 is the coefficient of speed fluctuation of a flywheel then the ratio of 
will be- a)
- b)
- c)
- d)
Correct answer is option 'D'. Can you explain this answer?
If C1 is the coefficient of speed fluctuation of a flywheel then the ratio of will be
will bea)
b)
c)
d)
|
|
Sinjini Bose answered |
We know that coefficient of fluctuation of speed (C1) is
Or, C1 ωmax + C1 ωmin = 2ωmax – 2ωmin
A crank of radius 15 cm is rotating at 50 rpm with an angular acceleration of 60 rad/sec2. The tangential acceleration of the crank is about- a)9 m/s2
- b)8 m/s2
- c)9.5 m/s2
- d)10.5 m/s2
Correct answer is option 'A'. Can you explain this answer?
A crank of radius 15 cm is rotating at 50 rpm with an angular acceleration of 60 rad/sec2. The tangential acceleration of the crank is about
a)
9 m/s2
b)
8 m/s2
c)
9.5 m/s2
d)
10.5 m/s2
|
|
Yash Das answered |
Tangential Acceleration at = rα
α = Angular acceleration = 60 rad/s2
r = radius of crank = 15 cm
∴ at = rα = 60 × 0.15 = 9 m/s
Chapter doubts & questions for Theory of Machines (TOM) - Mock Test Series for SSC JE Mechanical Engineering 2025 2025 is part of Mechanical Engineering exam preparation. The chapters have been prepared according to the Mechanical Engineering exam syllabus. The Chapter doubts & questions, notes, tests & MCQs are made for Mechanical Engineering 2025 Exam. Find important definitions, questions, notes, meanings, examples, exercises, MCQs and online tests here.
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