All questions of Force Method of Analysis for Civil Engineering (CE) Exam

Detailed Answer:



The statement "Indeterminate analysis of a symmetrical structure is difficult from that of a non-symmetric one" is false. Indeterminate analysis refers to the calculation of unknown reactions, internal forces, and displacements in a structure. While the presence of symmetry simplifies the analysis, it does not necessarily make it more difficult.



Symmetry in Structures: A structure is considered symmetrical when it possesses a balanced arrangement of its elements or components. This can include symmetry about a central axis, as well as symmetry about a plane or multiple planes. Symmetry is a common feature in many structures, such as buildings, bridges, and machines.

Advantages of Symmetry: The presence of symmetry in a structure offers several advantages:

1. Simplification of Geometry: Symmetry allows for the simplification of the structure's geometry, as certain elements or sections can be mirrored or replicated. This simplification reduces the number of unknowns in the analysis.

2. Reduction of Unknown Forces: Symmetry ensures that certain forces or reactions are balanced, eliminating the need to calculate them separately. This reduces the complexity of the analysis.

3. Conservation of Energy: Symmetry often leads to the conservation of energy in a structure, as forces and displacements are evenly distributed. This can simplify the determination of internal forces and displacements.



Non-Symmetric Structures: Non-symmetrical structures do not possess a balanced arrangement of their elements or components. They can have irregular shapes, varied load distributions, or lack any form of symmetry.

Challenges of Non-Symmetrical Structures: The analysis of non-symmetrical structures can be more challenging due to the following reasons:

1. Complex Geometry: Non-symmetrical structures often have complex geometries, making it difficult to determine the internal forces and displacements accurately.

2. Varied Load Distribution: The load distribution in non-symmetrical structures is often uneven, leading to varying internal forces throughout the structure. Analyzing these variations requires more detailed calculations.

3. Increased Unknowns: Non-symmetrical structures typically have a higher number of unknown reactions and internal forces compared to symmetrical structures. This increases the complexity of the analysis.



In conclusion, the statement that indeterminate analysis of a symmetrical structure is difficult compared to a non-symmetrical one is false. Symmetry in a structure simplifies the analysis by reducing unknowns, simplifying geometry, and conserving energy. Non-symmetrical structures, on the other hand, present challenges such as complex geometry, varied load distribution, and increased unknowns. Therefore, while the analysis of non-symmetrical structures may be more complex, the presence of symmetry in a structure does not necessarily make the analysis more difficult.

Air

Primary backup protection is the first line of defense in a power system to protect the equipment from faults and abnormal conditions. It is designed to provide fast and reliable protection in case of any abnormalities.

In the given components, the option 'D' - Equipment to be protected, can be common for primary backup protection. Here's why:

Equipment Protection:
- The primary objective of backup protection is to ensure the safety and integrity of the equipment in the power system.
- Equipment such as transformers, generators, motors, and other electrical devices are susceptible to faults and abnormal conditions that can lead to damage or failure.
- Primary backup protection is designed to detect these faults and disconnect the faulty equipment from the power supply to prevent further damage.

Importance of Equipment Protection:
- Equipment in a power system is expensive and vital for the operation of the system.
- Faults or abnormalities in equipment can lead to power outages, damage to other equipment, and even safety hazards.
- Protection systems are installed to minimize the impact of faults and ensure the reliability and longevity of the equipment.

Primary Backup Protection:
- Primary backup protection operates quickly and independently to detect faults and isolate the faulty equipment.
- It is designed to provide a reliable and fast response to faults, ensuring the safety and integrity of the equipment.
- The primary backup protection system typically includes protective relays, which are devices that monitor electrical parameters and can trip circuit breakers to isolate the faulty equipment.

Role of Other Components:
- Circuit breakers (option 'A') are essential components of the primary backup protection system as they are responsible for disconnecting the faulty equipment from the power supply.
- Current transformers (option 'B') are used to measure the current flowing through the equipment and provide input to the protective relays for fault detection.
- The battery room (option 'C') is not directly related to primary backup protection. However, it may provide backup power for the protection system in case of a power failure.

Conclusion:
While circuit breakers and current transformers are crucial components of the primary backup protection system, the equipment to be protected (option 'D') is common to all protection schemes. The primary backup protection is designed to ensure the safety and integrity of the equipment in the power system by detecting faults and isolating the faulty equipment.

Bimetallic strip as a passive transducer:

A bimetallic strip is a device that consists of two different metals bonded together. It is commonly used as a passive transducer in various applications. A passive transducer is a device that converts one form of energy into another without requiring an external power source.

Explanation:

1. Passive transducer definition:
- A passive transducer converts one form of energy into another without the need for an external power source.
- It relies on the physical properties of the material or components used in its construction.

2. Bimetallic strip definition:
- A bimetallic strip is made up of two different metals with different coefficients of thermal expansion.
- The two metals are bonded together, usually by welding or riveting, to form a flat strip.

3. Operating principle:
- When the bimetallic strip is subjected to temperature changes, the two metals expand or contract at different rates.
- This results in the strip bending or curving due to the unequal expansion or contraction.
- The amount of bending or curving of the strip is directly proportional to the temperature difference.

4. Working as a passive transducer:
- The bending or curving of the bimetallic strip can be used to measure temperature or to control mechanical devices.
- In temperature measurement applications, the strip is connected to a pointer or dial, allowing the temperature to be read directly.
- In mechanical control applications, the strip is used to actuate switches or valves based on temperature changes.

5. Advantages of a bimetallic strip as a passive transducer:
- It is a simple and cost-effective device.
- It has a wide temperature range of operation.
- It is reliable and durable due to its mechanical nature.
- It does not require an external power source for operation.

In conclusion, a bimetallic strip is classified as a passive transducer because it converts temperature changes into mechanical displacement without requiring an external power source. It is widely used in various applications due to its simplicity, reliability, and cost-effectiveness.

A Capacitor Start Motors are a single phase Induction Motor that employs a capacitor in the auxiliary winding circuit to produce a greater phase difference between the current in the main and the auxiliary windings. The name capacitor starts itself shows that the motor uses a capacitor for the purpose of the starting.In phase induction motors, we are unable to get starting torque, So we mostly use permanent capacitor split phase starting method in ceiling fans. Its main aim is to split the single phase supply into  phases, having time displacement of 90 degrees, also mechanically the windings are placed 90 degrees in space. It gives an rmf which produces a starting torque & makes it a self starting motor. So, the capacitor used in the other auxiliary winding mainly provides this 90 degrees time displacement. An inductor can also be used, but it has the following drawbacksBulky size of the inductor.Leakage reactance of it affects the value of the starting torque.Its delay in current affects the transients.

Step 1:5 and 1 ohm resistors are in series which gives 6 ohms
step 2: 6 and 3 are in parallel which gives 2 ohms and this 2 ohm is in series with 2ohms which gives 4 ohms
step 3: 6ohms and 4 ohms are in parallel the resultant resistance is 2.4 ohms
step 4:2.4 is in series with 8 and 4 which gives 2.4+4+8=14.4ohms

Resistance of Field Regulator in DC Shunt Motor

Field regulator is an important component in a DC shunt motor which is responsible for controlling the field current. The resistance of the field regulator determines the amount of current flowing through the field winding, thereby influencing the motor's speed and torque characteristics.

The resistance of the field regulator is typically specified in ohms and is denoted by the symbol 'Rf'. It is important to choose the appropriate resistance value for the field regulator to ensure optimal motor performance.

The resistance of the field regulator is determined based on various factors such as motor design, voltage rating, and desired operating characteristics. In the case of a DC shunt motor, the resistance of the field regulator is typically in the range of 100 ohms.

Explanation:

1. DC Shunt Motor:
- A DC shunt motor is a type of DC motor where the field winding is connected in parallel (shunt) with the armature winding.
- It is widely used in various applications due to its simple construction, good speed regulation, and ability to provide high starting torque.

2. Field Regulator:
- The field regulator is a device that controls the field current in a DC shunt motor.
- It consists of a variable resistance connected in series with the field winding.
- By adjusting the resistance, the field current can be varied, thereby controlling the motor's speed and torque characteristics.

3. Importance of Field Regulator Resistance:
- The resistance of the field regulator determines the amount of current flowing through the field winding.
- A higher resistance value reduces the field current, resulting in a slower motor speed.
- Conversely, a lower resistance value increases the field current, leading to a higher motor speed.

4. Order of Resistance:
- The given question states that the resistance of the field regulator in a DC shunt motor is of the order of 100 ohms.
- The term "order" refers to the magnitude of the resistance value.
- In this case, the resistance value is approximately 100 ohms, which is the correct answer (option 'A').

In conclusion, the resistance of the field regulator in a DC shunt motor is typically in the range of 100 ohms. This resistance value plays a crucial role in controlling the field current and, subsequently, the speed and torque characteristics of the motor.

Monopole:
Monopole consists of a single charge, which means it has only one type of charge present, either positive or negative.

Explanation:
Monopole is a theoretical concept in physics that describes a single isolated charge. In a monopole, there is no accompanying opposite charge to balance it out, unlike in a dipole where positive and negative charges are present.

Characteristics of a Monopole:
- It has a single charge, either positive or negative.
- Monopoles are theoretical as no isolated magnetic monopoles have been discovered yet.
- In theory, monopoles would have quantized magnetic charge similar to electric charge.

Relevance:
Monopoles are important in the study of electromagnetism and theoretical physics. The existence of magnetic monopoles could have significant implications for our understanding of the universe and fundamental forces.
In conclusion, a monopole consists of a single charge, making it distinct from dipoles which have both positive and negative charges.