Machine Design

Q1: According to Guest's theory, the failure occurs at a point in a member when the maximum shear stress in a bi-axial stress system reaches the shear stress at elastic limit in simple tension test.

A True

B False

Q2: A screw is said to be over hauling screw, if its efficiency is

A less than 50%

B more than 50%

C equal to 50%

D none of these

Q3: The load cup of a screw jack is made separate from the head of the spindle to

A enhance the load carrying capacity of the jack

B reduce the effort needed for lifting the working load

C prevent the rotation of load being lifted

D reduce the value of frictional torque

Q4: 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

Q5: The pipe joint mostly used for pipes carrying water at low pressures is

A socket joint

B nipple joint

C union joint

D spigot and socket joint

Q6: In order to avoid tearing of the plate at an edge, the distance from the centre line of the rivet hole to the nearest edge of the plate should be equal to (where d = Diameter of rivet hole)

A d

B 1.5 d


D 2.5 d

Q7: In radial cams, the follower moves

A in a direction perpendicular to the cam axis

B in a direction parallel to the cam axis

C in any direction irrespective of cam axis

D along the cam axis

Q8: A flanged pipe joint will be a leak-proof joint, if the circumferential pitch of the bolts is (where d = Diameter of bolt hole)

A less than 20 d

B greater than 30 d

C between 20 d and 30 d

D equal to inside diameter of pipe

Q9: Screws used for power transmission should have

A Low efficiency

B high efficiency

C very fine threads

D strong teeth

Q10: The number of rivets in shear shall be equal to the number of rivets in crushing.

A Correct

B Incorrect

Q11: In order to obtain the bolts of uniform strength, an axial hole is drilled through the head as far as the threaded portion such that the area of shank becomes equal to the root area of the thread.

A True

B False

Q12: The resistance to fatigue of a material is measured by

A elastic limit

B Young's modulus

C ultimate tensile strength

D endurance limit

Q13: According to I.B.R., shearing resistance required to shear off the rivet per pitch length (in double shear) is (where n = Number of rivets per pitch length)

A d2 x τ x n

B 1.875 x d2 x τ x n

C 2 x d2 x τ x n

D 3 x d2x τ x n

Q14: 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

Q15: A crankshaft is a __________ shaft.

A transmission

B machine

Q16: When a bolt is subjected to shock loading, the resilience of the bolt should be considered in order to prevent breakage at the

A head

B shank

C thread

D middle

Q17: The centre distance between two meshing involute gears is equal to





Q18: The velocity of sliding __________ the distance of the point of contact from the pitch point.

A is directly proportional to

B is inversely proportional to

C is equal to cos φ multiplied by

D does not depend upon

Q19: Two shafts A and B under pure torsion are of identical length and identical weight and are made of the same material. The shaft A is solid and the shaft B is hollow. We can say that

A shaft B is better than shaft A

B shaft A is better than shaft B

C both the shafts are equally good

Q20: The ball bearings are provided with a cage

A to reduce friction

B to facilitate slipping of balls

C to prevent the lubricant from flowing out

D to maintain the balls at a fixed distance apart

Q21: Which of the following statement is wrong ?

A The power transmitted by V-belts is less than flat belts for the same coefficient of friction, arc of contact and allowable tension in the belts

B The V-belt drive is used with large centre distance

C The V-belt may be operated in either direction with tight side of the belt at the top or bottom

D The ratio of driving tensions in V-belt drive is more than flat belt drives

Q22: In a hydrodynamic lubricated bearing

A there is a thick film of lubricant between the journal and the bearing

B there is a thin film of lubricant between the journal and the bearing

C there is no lubricant between the journal and the bearing

D the lubricant is forced between the journal and the bearing, by external pressure

Q23: An open belt drive is used when

A shafts are arranged parallel and rotate in the opposite directions

B shafts are arranged parallel and rotate in the same directions

C shafts are arranged at right angles and rotate in one definite direction

D driven shaft is to be started or stopped whenever desired without interferring with the driving shaft

Q24: The toughness of a material __________ when it is heated.

A increases

B decreases

C does not change

Q25: In second type of levers,

A load is in between the fulcrum and effort

B effort is in between the fulcrum and load

C fulcrum is in between the load and effort

D none of these

Q26: For unequal width of butt straps, the thickness of butt straps are

A 0.75 t for wide strap on the inside and 0.625 t for narrow strap on the outside

B 0.75 t for narrow strap on the inside and 0.625 t for wide strap on the outside

C 0.75 t for both the straps on the inside and outside

D 0.625 t for both the straps on the inside and outside

Q27: The sleeve or muff coupling is designed as a

A dun cylinder

B thick cylinder

C solid shaft

D hollow shaft

Q28: The number of slots in a 25 mm castle nut is

A 2

B 4

C 6

D 8

Q29: Soderberg relation is based on __________ of the material whereas all other failure relation for dynamic loading are based on ultimate strength of the material.

A elastic strength

B yield strength

C shear strength

Q30: In unilateral system of tolerance, the tolerance is allowed on

A one side of the actual size

B one side of the nominal size

C both sides of the actual size

D both sides of the nominal size

Q31: Circumferential joint in boilers is used to get the required length of a boiler.

A True

B False

Q32: Which of the following material has the maximum ductility?

A Mild steel

B Copper

C Zinc

D Aluminium

Q33: The square threads are not so strong as V-threads but they offer less frictional resistance to motion than Whitworth threads.

A Correct

B Incorrect

Q34: A plate with an elliptical hole in the centre, with semi-major axis (a) perpendicular to the direction of loading and semi-minor axis (b) along the direction of loading, is subjected to a pull P. The maximum stress induced at the edge of the hole is equal to (where σ = Stress for a plate with no hole i.e. nominal stress)





Q35: For maximum power, the velocity of the belt will be




D none of these

Q36: Surface endurance limit of gear material is dependent upon its

A elastic strength

B yield strength

C brinell hardness number

D toughness

Q37: The value of stress concentration factor depends upon

A material of the part

B geometry of the part

C material and geometry of the part

D none of these

Q38: In a flange coupling, the thickness of flanges is taken as one-half the diameter of shaft.

A Agree

B Disagree

Q39: According to Indian standard specifications, 100 H6/g5 means that the

A actual size is 100 mm

B basic size is 100 mm

C difference between the actual size and basic size is 100 mm

D none of the above

Q40: Which of the following statement is correct for gears?

A The addendum is less than dedendum

B The pitch circle diameter is equal to the product of module and number of teeth

C The pitch circle is always greater than the base circle

D all of the above

Q41: Slenderness ratio is the ratio of

A maximum size of column to minimum size of column

B width of column to depth of column

C effective length of column to least radius of gyration of the column

D effective length of column to width of column

Q42: The application of third type levers is found in

A handle of a hand pump

B hand wheel of a punching press

C lever of a loaded safety valve

D a pair of tongs

Q43: A column is known as a long column if the slenderness ratio is

A 40

B 50

C 70

D 100

Q44: In a flange coupling, the flanges are coupled together by means of

A bolts and nuts

B studs

C headless taper bolts

D none of these

Q45: A sliding bearing in which the working surfaces are completely separated from each other by lubricant is called zero film bearing.

A True

B False

Q46: A transmission shaft includes

A counter shaft

B line shaft

C over head shaft

D all of these

Q47: Stress concentration is caused due to

A variations in load acting on a member

B variations in properties of materials in a member

C abrupt change of cross-section

D all of these

Q48: According to Unwin's formula, the relation between the diameter of rivet hole (d) and the thickness of plate (t) is given by (where d and t are in mm)

A d = t

B d = 1.6 t

C d = 2 t

D d = 6 t

Q49: The constant factor in case of R10 series of preferred numbers is

A 1.06

B 1.12

C 1.26

D 1.58

Q50: When bevel gears connect two shafts whose axes intersect at an angle greater than a right angle and one of the bevel gears has a pitch angle of 90°, then they are known as

A angular bevel gears

B crown bevel gears

C internal bevel gears

D mitre gears

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