Power Screws Mechanical Design Questions Answers - Set 01 - ObjectiveBooks

Power Screws Mechanical Design Questions Answers - Set 01

Practice Test: Question Set - 01


1. A screw is said to be self-locking if its efficiency is
    (A) Equal to 50%
    (B) More than 50%
    (C) Less than 50%
    (D) None of the above

2. The maximum efficiency of square threaded power is
    (A) 1 - sin α/1 + sin α
    (B) 1 + sin α/1 - sin α
    (C) 1 - tan α/1 + tan α
    (D) 1 + tan α/1 - tan α

Where, φ = friction angle


3. A power screw is specified by
    (A) Major diameter × pitch
    (B) Major diameter × length
    (C) Mean diameter × pitch
    (D) Nominal major diameter

4. Which of the following screw thread is used for lead screw of lathe?
    (A) Square threads
    (B) Trapezoidal threads
    (C) Buttress threads
    (D) V-threads

5. Which of the following screw thread is used for jacks, vices and clamps?
    (A) Square threads
    (B) Trapezoidal threads
    (C) Buttress threads
    (D) Acme threads

6. The efficiency of square threaded power is maximum when
    (A) α = 60° - φ
    (B) α = 45° - φ
    (C) α = 45° + φ/2
    (D) α = 45° - φ/2

Where, α = helix angle, φ = friction angle


7. The maximum efficiency of square threaded power with friction angle of 30° is
    (A) 25 %
    (B) 33 %
    (C) 47 %
    (D) 41 %

8. Which of the following screw thread is used for transmitting force in one direction?
    (A) Square threads
    (B) Trapezoidal threads
    (C) Buttress threads
    (D) V-threads

9. A screw is said to be over hauling if its efficiency is
    (A) Equal to 50%
    (B) More than 50%
    (C) Less than 50%
    (D) None of the above

10. The efficiency of square threaded power depends upon
    (A) Mean diameter of screw
    (B) Coefficient of friction
    (C) Pitch of screw
    (D) All the above

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