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Machine Design Practice Test: Power Screws
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Avg score: 69% Most missed: “Tr 40 x 14(P 7), here 14 indicates”
Power Screws topics include: Concepts of power screws, self locking screws and screw efficiency. A power screw, also known as a lead screw, is a mechanical device that converts rotary motion into linear motion. They can be used to lift or move large loads, and are capable of a large mechanical advantage.  Power screws are used to transfer power, as opposed to threaded fasteners, which are used to clamp the machine members.  They have many advantages, including: Large load carrying capability Simple to design Easy to manufacture Large mechanical advantage Precise and accurate linear... Show more
Machine Design Practice Test: Power Screws
Time left 00:00
22 Questions

1. Which of the following are true?
2. V threads are highly recommended for fastening as well as power transmission purpose.
3. If friction angle is 30’ then the maximum efficiency of the screw is
4. A power screw has no problem of wear as there is very less amount of friction associated.
5. Cold rolled components have higher strengths and hardness than hot rolled components.
6. Efficiency of the screw depends upon helix angle but does not depend on friction angle.
7. Which of the following are true?
8. If the load itself begin to the screw and descend down, unless a restraining torque is applied then the condition is termed as
9. Depending upon the holding arrangement, power screws operate in how many different arrangements.
10. Nominal diameter of the screw thread is the same as core diameter.
11. Maximum efficiency of a square threaded is given by
12. In trapezoidal threads, f (coefficient of friction) can be taken as
13. Trapezoidal threads screws have less load carrying capacity as compared to square thread screws.
14. Maximum possible efficiency of a self-locking screw is
15. Efficiency of screw depends upon lead of the screw.
16. In trapezoidal threads, f (coefficient of friction) can be taken as
17. If nominal diameter of screw thread=50mm and pitch=10mm then the mean diameter of the screw thread will be?
18. Which of the following are true for buttress threads?
19. Nominal diameter of the screw thread is the same as core diameter.
20. Trapezoidal threads are better than square threads as there is radial pressure or side thrust on the nut.
21. V threads are highly recommended for fastening as well as power transmission purpose.
22. A power screw is only used to convert rotary motion into linear motion and not for transmitting power.