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Consider the follow ing statem ents regarding power screws.
1. The efficiency of self locking screw cannot be more than 50%.
2. If friction angle is less than the helix angle of the screw, then the efficiency will be more than 50%.
3. The efficiency of ACME (Trapezoidal) thread is less than that of square thread.
Q. Which of these statements are correct?
1. The efficiency of self locking screw cannot be more than 50%.
2. If friction angle is less than the helix angle of the screw, then the efficiency will be more than 50%.
3. The efficiency of ACME (Trapezoidal) thread is less than that of square thread.
Q. Which of these statements are correct?
- a)1, 2 and 3
- b)2 and 3
- c)1 and 3
- d)1 and 2
Correct answer is option 'C'. Can you explain this answer?
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Consider the follow ing statem ents regarding power screws.1. The effi...
η less than 50% so statement 1 correct α > φ statements 2 incorrect
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Consider the follow ing statem ents regarding power screws.1. The effi...
Statement 1: The efficiency of self-locking screw cannot be more than 50%.
The efficiency of a power screw is defined as the ratio of the useful work output to the work input. In the case of a self-locking screw, it is designed in such a way that it resists motion caused by an external force when the load is removed. This means that the screw has a high resistance to back-driving.
When a self-locking screw is being driven, the input work is done against the frictional forces between the screw and the nut. However, when the screw is self-locking, the output work is zero since the load is not moving. Therefore, the efficiency of a self-locking screw is always less than 100%.
Statement 2: If the friction angle is less than the helix angle of the screw, then the efficiency will be more than 50%.
The efficiency of a power screw is influenced by the friction angle, which is the angle between the helix angle and the tangent to the thread at the point of contact. The friction angle determines the frictional forces between the screw and the nut during operation.
If the friction angle is less than the helix angle, it means that the tangent to the thread at the point of contact is less steep than the helix angle. This results in a smaller component of the load being converted into frictional forces. As a result, the useful work output increases and the efficiency of the screw improves. Therefore, statement 2 is correct.
Statement 3: The efficiency of ACME (Trapezoidal) thread is less than that of a square thread.
The efficiency of a power screw is also influenced by the thread form. The ACME thread and the square thread are two common thread forms used in power screws.
The ACME thread has a trapezoidal shape with a larger thread angle compared to the square thread. The larger thread angle of the ACME thread results in a higher friction angle, which leads to higher frictional forces during operation. This reduces the useful work output and lowers the efficiency of the screw compared to a square thread. Therefore, statement 3 is correct.
Conclusion:
Based on the explanations above, statements 1 and 3 are correct. Therefore, the correct answer is option C - 1 and 3.
The efficiency of a power screw is defined as the ratio of the useful work output to the work input. In the case of a self-locking screw, it is designed in such a way that it resists motion caused by an external force when the load is removed. This means that the screw has a high resistance to back-driving.
When a self-locking screw is being driven, the input work is done against the frictional forces between the screw and the nut. However, when the screw is self-locking, the output work is zero since the load is not moving. Therefore, the efficiency of a self-locking screw is always less than 100%.
Statement 2: If the friction angle is less than the helix angle of the screw, then the efficiency will be more than 50%.
The efficiency of a power screw is influenced by the friction angle, which is the angle between the helix angle and the tangent to the thread at the point of contact. The friction angle determines the frictional forces between the screw and the nut during operation.
If the friction angle is less than the helix angle, it means that the tangent to the thread at the point of contact is less steep than the helix angle. This results in a smaller component of the load being converted into frictional forces. As a result, the useful work output increases and the efficiency of the screw improves. Therefore, statement 2 is correct.
Statement 3: The efficiency of ACME (Trapezoidal) thread is less than that of a square thread.
The efficiency of a power screw is also influenced by the thread form. The ACME thread and the square thread are two common thread forms used in power screws.
The ACME thread has a trapezoidal shape with a larger thread angle compared to the square thread. The larger thread angle of the ACME thread results in a higher friction angle, which leads to higher frictional forces during operation. This reduces the useful work output and lowers the efficiency of the screw compared to a square thread. Therefore, statement 3 is correct.
Conclusion:
Based on the explanations above, statements 1 and 3 are correct. Therefore, the correct answer is option C - 1 and 3.
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Consider the follow ing statem ents regarding power screws.1. The efficiency of self locking screw cannot be more than 50%.2. If friction angle is less than the helix angle of the screw, then the efficiency will be more than 50%.3. The efficiency of ACME (Trapezoidal) thread is less than that of square thread.Q.Which of these statements are correct?a)1, 2 and 3b)2 and 3c)1 and 3 d)1 and 2Correct answer is option 'C'. Can you explain this answer?
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Consider the follow ing statem ents regarding power screws.1. The efficiency of self locking screw cannot be more than 50%.2. If friction angle is less than the helix angle of the screw, then the efficiency will be more than 50%.3. The efficiency of ACME (Trapezoidal) thread is less than that of square thread.Q.Which of these statements are correct?a)1, 2 and 3b)2 and 3c)1 and 3 d)1 and 2Correct answer is option 'C'. Can you explain this answer? for Mechanical Engineering 2024 is part of Mechanical Engineering preparation. The Question and answers have been prepared according to the Mechanical Engineering exam syllabus. Information about Consider the follow ing statem ents regarding power screws.1. The efficiency of self locking screw cannot be more than 50%.2. If friction angle is less than the helix angle of the screw, then the efficiency will be more than 50%.3. The efficiency of ACME (Trapezoidal) thread is less than that of square thread.Q.Which of these statements are correct?a)1, 2 and 3b)2 and 3c)1 and 3 d)1 and 2Correct answer is option 'C'. Can you explain this answer? covers all topics & solutions for Mechanical Engineering 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for Consider the follow ing statem ents regarding power screws.1. The efficiency of self locking screw cannot be more than 50%.2. If friction angle is less than the helix angle of the screw, then the efficiency will be more than 50%.3. The efficiency of ACME (Trapezoidal) thread is less than that of square thread.Q.Which of these statements are correct?a)1, 2 and 3b)2 and 3c)1 and 3 d)1 and 2Correct answer is option 'C'. Can you explain this answer?.
Consider the follow ing statem ents regarding power screws.1. The efficiency of self locking screw cannot be more than 50%.2. If friction angle is less than the helix angle of the screw, then the efficiency will be more than 50%.3. The efficiency of ACME (Trapezoidal) thread is less than that of square thread.Q.Which of these statements are correct?a)1, 2 and 3b)2 and 3c)1 and 3 d)1 and 2Correct answer is option 'C'. Can you explain this answer? for Mechanical Engineering 2024 is part of Mechanical Engineering preparation. The Question and answers have been prepared according to the Mechanical Engineering exam syllabus. Information about Consider the follow ing statem ents regarding power screws.1. The efficiency of self locking screw cannot be more than 50%.2. If friction angle is less than the helix angle of the screw, then the efficiency will be more than 50%.3. The efficiency of ACME (Trapezoidal) thread is less than that of square thread.Q.Which of these statements are correct?a)1, 2 and 3b)2 and 3c)1 and 3 d)1 and 2Correct answer is option 'C'. Can you explain this answer? covers all topics & solutions for Mechanical Engineering 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for Consider the follow ing statem ents regarding power screws.1. The efficiency of self locking screw cannot be more than 50%.2. If friction angle is less than the helix angle of the screw, then the efficiency will be more than 50%.3. The efficiency of ACME (Trapezoidal) thread is less than that of square thread.Q.Which of these statements are correct?a)1, 2 and 3b)2 and 3c)1 and 3 d)1 and 2Correct answer is option 'C'. Can you explain this answer?.
Solutions for Consider the follow ing statem ents regarding power screws.1. The efficiency of self locking screw cannot be more than 50%.2. If friction angle is less than the helix angle of the screw, then the efficiency will be more than 50%.3. The efficiency of ACME (Trapezoidal) thread is less than that of square thread.Q.Which of these statements are correct?a)1, 2 and 3b)2 and 3c)1 and 3 d)1 and 2Correct answer is option 'C'. Can you explain this answer? in English & in Hindi are available as part of our courses for Mechanical Engineering.
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Consider the follow ing statem ents regarding power screws.1. The efficiency of self locking screw cannot be more than 50%.2. If friction angle is less than the helix angle of the screw, then the efficiency will be more than 50%.3. The efficiency of ACME (Trapezoidal) thread is less than that of square thread.Q.Which of these statements are correct?a)1, 2 and 3b)2 and 3c)1 and 3 d)1 and 2Correct answer is option 'C'. Can you explain this answer?, a detailed solution for Consider the follow ing statem ents regarding power screws.1. The efficiency of self locking screw cannot be more than 50%.2. If friction angle is less than the helix angle of the screw, then the efficiency will be more than 50%.3. The efficiency of ACME (Trapezoidal) thread is less than that of square thread.Q.Which of these statements are correct?a)1, 2 and 3b)2 and 3c)1 and 3 d)1 and 2Correct answer is option 'C'. Can you explain this answer? has been provided alongside types of Consider the follow ing statem ents regarding power screws.1. The efficiency of self locking screw cannot be more than 50%.2. If friction angle is less than the helix angle of the screw, then the efficiency will be more than 50%.3. The efficiency of ACME (Trapezoidal) thread is less than that of square thread.Q.Which of these statements are correct?a)1, 2 and 3b)2 and 3c)1 and 3 d)1 and 2Correct answer is option 'C'. Can you explain this answer? theory, EduRev gives you an
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