MCQs of Power Screws and Threaded Joints (Fundamentals of Machine Design - 3141907)

Fundamentals of Machine Design (3141907) MCQs

MCQs of Power Screws and Threaded Joints

Showing 11 to 20 out of 22 Questions

11.

When screw threads are to be used in a situation where power is being transmitted in one direction only, then the screw threads suitable for this will be

(a)	square threads
(b)	acme threads
(c)	knuckle threads
(d)	buttress threads

12.

The railway carriage couplings have

(a)	square threads
(b)	acme threads
(c)	knuckle threads
(d)	buttress threads

13.

The acme threads are usually found on

(a)	spindles of bench vices
(b)	railway carriage couplings
(c)	feed mechanism of machine tools
(d)	lead screw of lathes

14.

The efficiency of a square threaded screw is maximum if the helix angle is equal to (where

ϕ

= Angle of friction)

(a)	$90^{o} - ϕ$
(b)	$45^{o} - ϕ$
(c)	$45^{o} - \frac{ϕ}{2}$
(d)	$45^{o} + \frac{ϕ}{2}$

15.

Which of the following statement is correct regarding power screws?

(a)	The efficiency of a self-locking screw can not be more than 50%
(b)	The efficiency of Acme (trapezoidal) thread is less than that of a square thread
(c)	If the friction angle is less than the helix angle of the screw, then the efficiency will be more than 50%
(d)	(A) and (B) Only

16.

Screws jacks have multiple threads.

(a)	Agree
(b)	Disagree

17.

Multiple threads are used to secure

(a)	low efficiency
(b)	high efficiency
(c)	high load lifting capacity
(d)	high mechanical advantage

18.

A screw will be self-locking, if

(a)	friction angle is less than helix angle
(b)	friction angle is more than helix angle
(c)	friction angle is equal to the helix angle
(d)	the efficiency of the screw is 100%

19.

A screw is said to be over hauling screw if the

(a)	friction angle is less than helix angle
(b)	friction angle is more than helix angle
(c)	friction angle is equal to the helix angle
(d)	the efficiency of the screw is 100%

20.

When the screw in a mechanical screw jack rotates, the load kept on the top of it moves

(a)	axially upwards
(b)	axially downwards
(c)	axially upwards or downwards
(d)	none of these

Showing 11 to 20 out of 22 Questions