A load of 15 kN is raised by means of a screw jack. The mean diameter of the square threaded screw is 42 mm and the pitch is 10 mm. A force of 120 N is applied at the end of a lever to raise the load. Is the screw self-locking?

Insufficient data to predict the result

If α denotes the lead angle and φ denotes the angle of friction, then the efficiency of the screw is given by

$\frac{tan~(\alpha~-~\phi)}{tan~\alpha}$

$\frac{tan~\alpha}{tan~(\alpha~-~\phi)}$

$\frac{tan~(\alpha~+~\phi)}{tan~\alpha}$

$\frac{tan~\alpha}{tan~(\alpha~+~\phi)}$

For the same pitch, the efficiency of screw jack with square threads is

dependent only on the load on the jack

A bolt of M 24 × 2 means that:

The effective diameter of bolt is 24 mm and there are 2 threads per cm

The pitch of the thread is 24 mm and depth is 2 mm

Cross-sectional area of the threads is 24 mm2

The nominal diameter of bolt is 24 mm and pitch is 2 mm

The effective diameter of bolt is 24 mm and there are 2 threads per cm

For a machine to be self sustaining, the relation between ϕ = Angle of friction and α = slope of thread, is

$\frac{\alpha }{\phi } = constant$

Find the torsional shear stress to which a screw of nominal diameter 22mm is subjected when the clamp exerts a force of 5kN on it. The screw is double threaded and pitch of screw is 5mm.Given: Coefficient of friction is 0.15.$

31.21N/mm¬¨¬®‚Äö√¢¬ß

25.45N/mm¬¨¬®‚Äö√¢¬ß

21.29N/mm¬¨¬®‚Äö√¢¬ß

31.21N/mm¬¨¬®‚Äö√¢¬ß

35.65N/mm¬¨¬®‚Äö√¢¬ß

Find_the_bending_stress_to_which_a_screw_of_nominal_diameter_22mm_is_subjected_when_the_clamp_exerts_a_force_of_5kN_acts_on_it._The_screw_is_double_threaded_and_pitch_of_screw_is_5mm.Given:_Coefficient_of_friction_is_0.15.It_is_assumed_operator_exerts_a_force_of_250N_at_the_handle_of_length_275mm.$

124.45N/mm¬¨¬®‚Äö√¢¬ß

123.45N/mm¬¨¬®‚Äö√¢¬ß

132.54N/mm¬¨¬®‚Äö√¢¬ß

142.54N/mm¬¨¬®‚Äö√¢¬ß

124.45N/mm¬¨¬®‚Äö√¢¬ß

If bending stress in a screw is of magnitude 95N/mm¬¨¬®‚Äö√¢¬ß and torsional shear stress of magnitude 15N/mm¬¨¬®‚Äö√¢¬ß, then what is the principal shear stress?$

48.7N/mm¬¨¬®‚Äö√¢¬ß

54.3 N/mm¬¨¬®‚Äö√¢¬ß

51.4 N/mm¬¨¬®‚Äö√¢¬ß

49.8 N/mm¬¨¬®‚Äö√¢¬ß

38 + Mcqs in Power Screws Numericals in Machine Design Page 1 McqOptions

1.	The nominal diameter of the screw is 22mm and the allowable bearing pressure for the nut is 15N//mm². Find the length of the nut if pitch of the screw is
A.	15mm
B.	20mm
C.	25mm
D.	30mm
Answer» B. 20mm

Discussion

2.	If bending stress in a screw is of magnitude 95N/mm² and torsional shear stress of magnitude 15N/mm², then what is the principal shear stress?
A.	48.7N/mm²
B.	54.3 N/mm²
C.	51.4 N/mm²
D.	49.8 N/mm²
Answer» E.

Discussion

3.	Find the torsional shear stress to which a screw of nominal diameter 22mm is subjected when the clamp exerts a force of 5kN on it. The screw is double threaded and pitch of screw is 5mm.Given: Coefficient of friction is 0.15.
A.	25.45N/mm²
B.	21.29N/mm²
C.	31.21N/mm²
D.	35.65N/mm²
Answer» C. 31.21N/mm²

Discussion

4.	Find the bending stress to which a screw of nominal diameter 22mm is subjected when the clamp exerts a force of 5kN acts on it. The screw is double threaded and pitch of screw is 5mm.Given: Coefficient of friction is 0.15.It is assumed operator exerts a force of 250N at the handle of length 275mm.
A.	123.45N/mm²
B.	132.54N/mm²
C.	142.54N/mm²
D.	124.45N/mm²
Answer» D. 124.45N/mm²

Discussion

5.	A machine vice whose length of the handle is 150mm and the coefficient of friction for thread and collar are 0.15 and 0.17 respectively has a force applied at handle of 125N. Also the outer and inner diameters of collar are 55mm and 45mm respectively. Find the overall efficiency if nominal diameter=22mm and pitch=5mm.
A.	18.12%
B.	12.18%
C.	21.23%
D.	23.21%
Answer» C. 21.23%

Discussion

6.	A machine vice whose length of the handle is 150mm and the coefficient of friction for thread and collar are 0.15 and 0.17 respectively has a force applied at handle of 125N. Also the outer and inner diameters of collar are 55mm and 45mm respectively. Find the clamping force W if nominal diameter=22mm and pitch=5mm.
A.	4539.45N
B.	2868.73N
C.	3657.56N
D.	2134.34N
Answer» C. 3657.56N

Discussion

7.	If for a trapezoidal thread, angle of thread is 15’ then what will be the replacement of the coefficient of friction which is 0.15.
A.	0.1553
B.	0.1335
C.	0.1667
D.	0.1776
Answer» B. 0.1335

Discussion

8.	For multi start thread, the distance between two adjacent thread is known as
A.	Pitch
B.	Lead
C.	Pitch diameter
D.	Nominal diameter
Answer» B. Lead

Discussion

9.	A double start thread has lead of 5 mm. The pitch of the thread is:
A.	5 mm
B.	10 mm
C.	2.5 mm
D.	None of these
Answer» D. None of these

Discussion

10.	A load of 15 kN is raised by means of a screw jack. The mean diameter of the square threaded screw is 42 mm and the pitch is 10 mm. A force of 120 N is applied at the end of a lever to raise the load. Is the screw self-locking?
A.	Yes
B.	No
C.	Insufficient data to predict the result
D.	None of the above
Answer» D. None of the above

Discussion

11.	A screw jack has a pitch of 12 mm with a mean radius of thread equal to 22.5 mm. A lever 600 mm long is used to raise a load of 1800 kg, the coefficient of friction is 0.10. Find the helix angle and friction angle.
A.	6.2° , 4.5°
B.	4.85°, 5.7°
C.	6.37°, 4.42°
D.	4.2°, 5.5°
Answer» C. 6.37°, 4.42°

Discussion

12.	For a power screw having square threads with lead angle of 45° and coefficient of friction of 0.15 between screw and nut, the efficiency of the power screw, neglecting collar friction, is given by
A.	74%
B.	64%
C.	54%
D.	44%
Answer» B. 64%

Discussion

13.	In a screw jack of lead angle α, the effort required to lift the load W is given by ___________ (ϕ = Friction Angle)
A.	P = W tan (α - ϕ)
B.	P = W tan (α + ϕ)
C.	P = W cos (α - ϕ)
D.	P = W cos (α + ϕ)
Answer» C. P = W cos (α - ϕ)

Discussion

14.	A screw having coefficient of friction equal to or greater than the tangent of the load angle is known as
A.	Machine screw
B.	Self locking screw
C.	Set-screws
D.	Ball-bearing type screws
Answer» C. Set-screws

Discussion

15.	A locking device in which the bottom cylindrical portion is recessed to receive the tip of the locking set screw, is called
A.	castle nut
B.	jam nut
C.	ring nut
D.	sawn nut
Answer» D. sawn nut

Discussion

16.	If α denotes the lead angle and φ denotes the angle of friction, then the efficiency of the screw is given by
A.	$\frac{tan~(\alpha~-~\phi)}{tan~\alpha}$
B.	$\frac{tan~\alpha}{tan~(\alpha~-~\phi)}$
C.	$\frac{tan~(\alpha~+~\phi)}{tan~\alpha}$
D.	$\frac{tan~\alpha}{tan~(\alpha~+~\phi)}$
Answer» E.

Discussion

17.	For power screw applications, a square thread can be preferred to a trapezoidal thread for
A.	easier manufacture
B.	better strength
C.	better efficiency
D.	more available standards
Answer» D. more available standards

Discussion

18.	For the same pitch, the efficiency of screw jack with square threads is
A.	more than that with V-threads
B.	less than that with V-threads
C.	same as that with V-threads
D.	dependent only on the load on the jack
Answer» B. less than that with V-threads

Discussion

19.	A fastener is threaded into a tapered hole, then the fastener is likely to be called as
A.	Screw
B.	Bolt
C.	Nail
D.	all the above
Answer» B. Bolt

Discussion

20.	A bolt of M 24 × 2 means that:
A.	The pitch of the thread is 24 mm and depth is 2 mm
B.	Cross-sectional area of the threads is 24 mm2
C.	The nominal diameter of bolt is 24 mm and pitch is 2 mm
D.	The effective diameter of bolt is 24 mm and there are 2 threads per cm
Answer» D. The effective diameter of bolt is 24 mm and there are 2 threads per cm

Discussion

21.	In a triple start thread, which of the following is true?[L = Lead, P = Pitch]
A.	L = P
B.	3L = P
C.	L = 3P
D.	L = 3 + P
Answer» D. L = 3 + P

Discussion

22.	For a machine to be self sustaining, the relation between ϕ = Angle of friction and α = slope of thread, is
A.	α = ϕ
B.	α < ϕ
C.	α > ϕ
D.	$\frac{\alpha }{\phi } = constant$
Answer» C. α > ϕ

Discussion

23.	In a hexagonal nut, width across flats by the approximate standard method is ______ (where D = nominal diameter).
A.	1.0 × D + 3 mm
B.	2 × D mm
C.	(1.5 × D) + 3 mm
D.	4 × D mm
Answer» D. 4 × D mm

Discussion

24.	A lead screw with half nuts in a lathe, free to rotate in both directions has
A.	V - threads
B.	Whitworth threads
C.	Buttress threads
D.	Acme threads
Answer» E.

Discussion

25.	A_MACHINE_VICE_WHOSE_LENGTH_OF_THE_HANDLE_IS_150MM_AND_THE_COEFFICIENT_OF_FRICTION_FOR_THREAD_AND_COLLAR_ARE_0.15_AND_0.17_RESPECTIVELY_HAS_A_FORCE_APPLIED_AT_HANDLE_OF_125N._ALSO_THE_OUTER_AND_INNER_DIAMETERS_OF_COLLAR_ARE_55MM_AND_45MM_RESPECTIVELY._FIND_THE_OVERALL_EFFICIENCY_IF_NOMINAL_DIAMETER=22MM_AND_PITCH=5MM.?$
A.	18.12%
B.	12.18%
C.	21.23%
D.	23.21%
Answer» C. 21.23%

Discussion

26.	Find the torsional shear stress to which a screw of nominal diameter 22mm is subjected when the clamp exerts a force of 5kN on it. The screw is double threaded and pitch of screw is 5mm.Given: Coefficient of friction is 0.15.$
A.	25.45N/mm¬¨¬®‚Äö√¢¬ß
B.	21.29N/mm¬¨¬®‚Äö√¢¬ß
C.	31.21N/mm¬¨¬®‚Äö√¢¬ß
D.	35.65N/mm¬¨¬®‚Äö√¢¬ß
Answer» C. 31.21N/mm¬¨¬®‚Äö√¢¬ß

Discussion

27.	Find_the_bending_stress_to_which_a_screw_of_nominal_diameter_22mm_is_subjected_when_the_clamp_exerts_a_force_of_5kN_acts_on_it._The_screw_is_double_threaded_and_pitch_of_screw_is_5mm.Given:_Coefficient_of_friction_is_0.15.It_is_assumed_operator_exerts_a_force_of_250N_at_the_handle_of_length_275mm.$
A.	123.45N/mm¬¨¬®‚Äö√¢¬ß
B.	132.54N/mm¬¨¬®‚Äö√¢¬ß
C.	142.54N/mm¬¨¬®‚Äö√¢¬ß
D.	124.45N/mm¬¨¬®‚Äö√¢¬ß
Answer» D. 124.45N/mm¬¨¬®‚Äö√¢¬ß

Discussion

28.	A fillet weld is an approximately triangular cross section joining two surfaces lying parallels to each other.
A.	True
B.	False
Answer» C.

Discussion

29.	A but joint can be defined as a joint between two components lying approximately in a different plane.
A.	True
B.	False
Answer» C.

Discussion

30.	The nominal diameter of the screw is 22mm and the allowable bearing pressure for the nut is 15N//mm¬¨¬®‚Äö√¢¬ß. Find the length of the nut if pitch of the screw is$
A.	15mm
B.	20mm
C.	25mm
D.	30mm
Answer» B. 20mm

Discussion

31.	If bending stress in a screw is of magnitude 95N/mm¬¨¬®‚Äö√¢¬ß and torsional shear stress of magnitude 15N/mm¬¨¬®‚Äö√¢¬ß, then what is the principal shear stress?$
A.	48.7N/mm¬¨¬®‚Äö√¢¬ß
B.	54.3 N/mm¬¨¬®‚Äö√¢¬ß
C.	51.4 N/mm¬¨¬®‚Äö√¢¬ß
D.	49.8 N/mm¬¨¬®‚Äö√¢¬ß
Answer» E.

Discussion

32.	A machine vice whose length of the handle is 150mm and the coefficient of friction for thread and collar are 0.15 and 0.17 respectively has a force applied at handle of 125N. Also the outer and inner diameters of collar are 55mm and 45mm respectively. Find the collar torque in terms of clamping force W assuming uniform wear theory if nominal diameter=22mm and pitch=5mm.
A.	4.5W
B.	5.4W
C.	4.25W
D.	3.37W
Answer» D. 3.37W

Discussion

33.	A machine vice whose length of the handle is 150mm and the coefficient of friction for thread and collar are 0.15 and 0.17 respectively has a force applied at handle of 125N. Also the outer and inner diameters of collar are 55mm and 45mm respectively. Find the screw torque in terms of clamping force W if nominal diameter=22mm and pitch=5mm.
A.	3.567W N-mm
B.	2.286W N-mm
C.	3.564W N-mm
D.	None of the mentioned
Answer» C. 3.564W N-mm

Discussion

34.	What will be efficiency of the screw in case of raising the load when coefficient of friction is 0.1553 and tangent of helix angle is 0.0813?
A.	34%
B.	45%
C.	54%
D.	43%
Answer» B. 45%

Discussion

35.	If for a trapezoidal thread, angle of thread is 15‚Äö√Ñ√∂‚àö√ë‚àö¬• then what will be the replacement of the coefficient of friction which is 0.15.$
A.	0.1553
B.	0.1335
C.	0.1667
D.	0.1776
Answer» B. 0.1335

Discussion

36.	For a double threaded screw, what will be the tangent of helix angle if nominal diameter and pitch are 100mm and 12mm respectively?
A.	0.045
B.	0.081
C.	0.094
D.	0.023
Answer» C. 0.094

Discussion

37.	What is the collar friction torque if outer and inner diameters are 100mm and 65mm respectively. Coefficient of friction is 0.15 and the load acting is of 15kN. Consider uniform wear theory.
A.	89886.6N-mm
B.	38796.5N-mm
C.	92812.5N-mm
D.	87645.5N-mm
Answer» D. 87645.5N-mm

Discussion

38.	Find the torque required to raise the load of 15kN and mean diameter of triple threaded screw being 46mm. Also given pitch=8mm and coefficient of friction is 0.15.
A.	11831.06N-mm
B.	11813.06N-mm
C.	12811.06N-mm
D.	None of the listed
Answer» B. 11813.06N-mm

Discussion

16.	If α denotes the lead angle and φ denotes the angle of friction, then the efficiency of the screw is given by
A.	\(\frac{tan~(\alpha~-~\phi)}{tan~\alpha}\)
B.	\(\frac{tan~\alpha}{tan~(\alpha~-~\phi)}\)
C.	\(\frac{tan~(\alpha~+~\phi)}{tan~\alpha}\)
D.	\(\frac{tan~\alpha}{tan~(\alpha~+~\phi)}\)
Answer» E.

Explore topic-wise MCQs in Machine Design.

The nominal diameter of the screw is 22mm and the allowable bearing pressure for the nut is 15N//mm². Find the length of the nut if pitch of the screw is

If bending stress in a screw is of magnitude 95N/mm² and torsional shear stress of magnitude 15N/mm², then what is the principal shear stress?

Find the torsional shear stress to which a screw of nominal diameter 22mm is subjected when the clamp exerts a force of 5kN on it. The screw is double threaded and pitch of screw is 5mm.Given: Coefficient of friction is 0.15.

Find the bending stress to which a screw of nominal diameter 22mm is subjected when the clamp exerts a force of 5kN acts on it. The screw is double threaded and pitch of screw is 5mm.Given: Coefficient of friction is 0.15.It is assumed operator exerts a force of 250N at the handle of length 275mm.

If for a trapezoidal thread, angle of thread is 15’ then what will be the replacement of the coefficient of friction which is 0.15.

For multi start thread, the distance between two adjacent thread is known as

A double start thread has lead of 5 mm. The pitch of the thread is:

A load of 15 kN is raised by means of a screw jack. The mean diameter of the square threaded screw is 42 mm and the pitch is 10 mm. A force of 120 N is applied at the end of a lever to raise the load. Is the screw self-locking?

A screw jack has a pitch of 12 mm with a mean radius of thread equal to 22.5 mm. A lever 600 mm long is used to raise a load of 1800 kg, the coefficient of friction is 0.10. Find the helix angle and friction angle.

For a power screw having square threads with lead angle of 45° and coefficient of friction of 0.15 between screw and nut, the efficiency of the power screw, neglecting collar friction, is given by

In a screw jack of lead angle α, the effort required to lift the load W is given by ___________ (ϕ = Friction Angle)

A screw having coefficient of friction equal to or greater than the tangent of the load angle is known as

A locking device in which the bottom cylindrical portion is recessed to receive the tip of the locking set screw, is called

If α denotes the lead angle and φ denotes the angle of friction, then the efficiency of the screw is given by

For power screw applications, a square thread can be preferred to a trapezoidal thread for

For the same pitch, the efficiency of screw jack with square threads is

A fastener is threaded into a tapered hole, then the fastener is likely to be called as

A bolt of M 24 × 2 means that:

In a triple start thread, which of the following is true?[L = Lead, P = Pitch]

For a machine to be self sustaining, the relation between ϕ = Angle of friction and α = slope of thread, is

In a hexagonal nut, width across flats by the approximate standard method is ______ (where D = nominal diameter).

A lead screw with half nuts in a lathe, free to rotate in both directions has

Find the torsional shear stress to which a screw of nominal diameter 22mm is subjected when the clamp exerts a force of 5kN on it. The screw is double threaded and pitch of screw is 5mm.Given: Coefficient of friction is 0.15.$

Find_the_bending_stress_to_which_a_screw_of_nominal_diameter_22mm_is_subjected_when_the_clamp_exerts_a_force_of_5kN_acts_on_it._The_screw_is_double_threaded_and_pitch_of_screw_is_5mm.Given:_Coefficient_of_friction_is_0.15.It_is_assumed_operator_exerts_a_force_of_250N_at_the_handle_of_length_275mm.$

A fillet weld is an approximately triangular cross section joining two surfaces lying parallels to each other.

A but joint can be defined as a joint between two components lying approximately in a different plane.

The nominal diameter of the screw is 22mm and the allowable bearing pressure for the nut is 15N//mm¬¨¬®‚Äö√¢¬ß. Find the length of the nut if pitch of the screw is$

If bending stress in a screw is of magnitude 95N/mm¬¨¬®‚Äö√¢¬ß and torsional shear stress of magnitude 15N/mm¬¨¬®‚Äö√¢¬ß, then what is the principal shear stress?$

What will be efficiency of the screw in case of raising the load when coefficient of friction is 0.1553 and tangent of helix angle is 0.0813?

If for a trapezoidal thread, angle of thread is 15‚Äö√Ñ√∂‚àö√ë‚àö¬• then what will be the replacement of the coefficient of friction which is 0.15.$

For a double threaded screw, what will be the tangent of helix angle if nominal diameter and pitch are 100mm and 12mm respectively?

What is the collar friction torque if outer and inner diameters are 100mm and 65mm respectively. Coefficient of friction is 0.15 and the load acting is of 15kN. Consider uniform wear theory.

Find the torque required to raise the load of 15kN and mean diameter of triple threaded screw being 46mm. Also given pitch=8mm and coefficient of friction is 0.15.