MCQ On Design Against Static Load
Q. A mechanical component may fail as a result of which of the following
A. elastic deflection
B. general yielding
C. fracture
D. each of the mentioned
.
Answer: A
Explanation: Failing simply means unable to perform its function satisfactorily.
Q. Type of load affects factor of safety.
A. True
B. False
.
Answer: A
Explanation: Dynamic load has higher factor of safety as compared to static loading.
Q. For cast iron components, which of the following strength are considered to be the failure criterion?
A. Ultimate tensile strength
B. Yield Strength
C. Endurance limit
D. None of the mentioned
.
Answer: A
Explanation: Ultimate tensile strength is the highest stress a component can undergo before failing and hence is used as a criterion.
Q. For components made of ductile materials like steel, subjected to static loading which of the following strength is used as a failure of criterion?
A. Yield strength
B. Ultimate strength
C. Endurance limit
D. None of the mentioned
.
Answer: A
Explanation: In elastic material there is considerable plastic deformation at yielding point.
Q. Pitting occurs on _____ of the component.
A. Surface
B. Inner body
C. Inside or on surface
D. outside
.
Answer: A
Explanation: Pitting is a process in which small holes occur on a surface of component.
Q. Buckling is elastic instability which leads to sudden large lateral deflection.
A. True
B. False
.
Answer: A
Explanation: Definition of buckling.
Q. The critical buckling load depends upon which of the following parameters?
A. Yield strength
B. Modulus of elasticity
C. Radius of gyration
D. Each of the mentioned
.
Answer: D
Explanation: It depends on moment of inertia(which further depends on radius of gyration), elasticity and yield strength.
Q. If there are residual stresses in the material, than lower factor of safety is used.
A. True
B. False
.
Answer: B
Explanation: Residual stress increases the chance of failure.
Q. Which of the following relationship is true? (p=Poisson’s ratio)
A. E=2G (1+p)
B. E=G (2+p)
C. E= 2(G+ p)
D. No relation exist between E, G and p
.
Answer: A
Explanation: Formula.
Q.. Modulus of rigidity for carbon steels is greater than that of grey cast iron.
A. True
B. False
.
Answer: A
Explanation: Modulus of rigidity is double for carbon steels as compared to grey cast iron.
Q.. According to principal stress theory, which option represents the correct relation between yield strength in shear (YSS) and the yield strength in tension (YST)?
A. YSS=0.5YST
B. YSS=0.577YST
C. YST=0.5YSS
D. YST=0.577YSS
.
Answer: A
Explanation: Shear diagonal is at 45’ and by equation of shear stress theory, the required relation is obtained.
Q.. A beam subjected to bending moment undergoes which of the following stresses?
A. Compressive
B. Tensile
C. Both compressive & tensile
D. None of the mentioned
.
Answer: C
Explanation: The portion above the neutral axis is under compression and the portion below it is under tensile stress.
Q. The bending stress varies _______ with the distance from the neutral axis.
A. Linearly
B. Inversely
C. Squarely
D. Bending stress is independent of distance from the neutral axis
.
Answer: A
Explanation: Bending Stress= (Bending Moment x distance from neutral axis/ Moment of inertiA..
Q. Cotter joint is used when the members are subjected to which type of stresses?
A. Axial tensile
B. Axial compressive
C. Axial tensile or compressive
D. None of the mentioned
.
Answer: C
Explanation: Cotter joint is used when axial forces are applied.
Q. The principle of wedge action is used in cotter joint.
A. True
B. False
.
Answer: A
Explanation: Wedge action imparts tightening to the cotter joint.
Q. Can the cotter joint be used to connect slide spindle and fork of valve mechanism?
A. True
B. False
.
Answer: A
Explanation: As long as axial forces act, cotter joint can be employed.
Q. Which of the following is not a part of cotter joint?
A. Socket
B. Spigot
C. Cotter
D. Collar
.
Answer: D
Explanation: There is no point of mentioning collar alone in a cotter joint. It has to be a spigot collar or socket collar.
Q. Cold riveting holds the connected parts better than hot riveting.
A. True
B. False
.
Answer: B
Explanation: The compression of connected parts in hot riveting causes friction, which resist sliding of one part with respect to other. This force is greater in hot riveting.
Q. In cold riveting like hot riveting shank is subjected to majorly tensile stress.
A. True
B. False
.
Answer: B
Explanation: In cold riveting there is no reduction in length and hence no tensile stress. Shear stress dominates.
Q. Determine the width of the cotter used in cotter joint connecting two rods subjected to axial load of 50kN and permissible shear stress in cotter is 50N/(mm² ). Given thickness of cotter=Q.mm
A. 5omm
B. Q.0mm
C. 150mm
D. 25mm
.
Answer: A
Explanation: Cotter is subjected to double shear hence width=P/(2*τ*t).
Q. If joint is to fail by crushing of socket collar then estimate the diameter of socket collar. Given Permissible compressive stress= Q.Q.67 N/mm².; Spigot dia=65mm; thickness 0f collar=15mm
A. 131mm
B. 139mm
C. 141mm
D. 149mm
.
Answer: A
Explanation: Compressive stress= P/ [(socket dia-spigot diA.*thickness].
Q. Cotter joint can be used to connect two rods for torque transmission purpose.
A. True
B. False
.
Answer: B
Explanation: Cotter Joint is never used to connect two rods for torque transmission purpose.
Q.. Thickness of plate is required more in welding than in riveting.
A. True
B. False
.
Answer: B
Explanation: In riveting, cross section is weakened due to the holes and to compensate this, thicker plates are required in riveting.
Q. Knuckle Joint can’t be used to connect two intersecting rods.
A. Yes
B. No, it can’t be used
C. It can be used with some modificatios
D. It is expensive and hence isn’t used
.
Answer: B
Explanation: Knuckle Joint is used to connect two rods whose axes coincide or intersect and lie in a same plane.
Q. A knuckle joint is unsuitable for two rotating shafts, which transmit torque
A. True
B. False
.
Answer: A
Explanation: Knuckle joint can’t be used for torque transmission.
Q. A maximum of how many roads may be connected using a knuckle joint?
A. 2
B. 3
C. 4
D. 5
.
Answer: B
Explanation: In rare explanation, two rods with forks and one rod with eye is connected.
Q. A knuckle joint is also called socket pin joint.
A. True
B. False
.
Answer: B
Explanation: A knuckle joint is also called a Forked Pin Joint.
Q. Which of the following are important parts of knuckle joint?
A. Eye
B. Pin
C. Fork
D. Each of the mentioned
.
Answer: D
Explanation: All the mentioned parts are important components of knuckle joint.
Q. Calculate the diameter of pin from shear consideration with maximum shear stress allowed is 40NN/mm² and an axial tensile force of 50kN is acting on the rod.
A. 39mm
B. 44mm
C. 49mm
D. 52mm
.
Answer: A
Explanation: As the pin is subjected to double shear diameter (D. = √(2P/π x τ) = 3Q.80mm.
Q. If knuckle joint is to fail by crushing failure of pin in fork, then determine the diameter of knuckle pin when 50kN axial tensile force act on rods. Given: Max allowable compressive stress=25N/mm², thickness of each eye of fork=25mm.
A. 40mm
B. 50mm
C. 60mm
D. 70mm
.
Answer: A
Explanation: d=P/2aσ = 40mm.
Q. If any cross section is subjected to direct tensile stress and bending stress, then find the dimension of cross section. Given length & breadth are t and 2t respectively. F=25kN acts on the top fibre of the cross section, M=F x t . Also maximum allowable tensile stress =Q.0N/mm².
A. 2Q.5mm
B. 30.2mm
C. 2Q.55mm
D. None of the mentioned
.
Answer: A
Explanation: σ= [P/A] + [My/I], where y=t & I=t(2t)ᴲ/Q..
Q. A knuckle joint can be used in valve mechanism of a reciprocating engine.
A. Yes
B. No
C. Yes but there are stress probles
D. No as it is very dangerous to use
.
Answer: A
Explanation: Knuckle joint can be used till the rods coincide or intersect in a plane.
Q.. Distortion energy theory is slightly liberal as compared to maximum shear stress theory.
A. True
B. False
.
Answer: A
Explanation: The hexagon of maximum shear theory falls completely inside the ellipse of distortion energy theorem.
Q. The normal stress is perpendicular to the area under considerations, while the shear stress acts over the area.
A. True
B. False
.
Answer: A
Explanation: This is the convention used.
Q. If a body is subjected to stresses in xy plane with stresses of 60N/mm² and 80N/mm² acting along x and y axes respectively. Also the shear stress acting is 20N/mm²Find the maximum amount of shear stress to which the body is subjected.
A. 2Q.4mm
B. 25mm
C. 2Q.3mm
D. 2Q.2mm
.
Answer: A
Explanation: τ(max)=√( [σ(x)-σ(y) ]²/2² + τ²).
Q. If a body is subjected to stresses in xy plane with stresses of 60N/mm² and 80N/mm² acting along x and y axes respectively. Also the shear stress acting is Q.N/mm². Find the inclination of the plane in which shear stress is maximal.
A. 45’
B. 30’
C. 60’
D. 15’
.
Answer: A
Explanation: tan (2Ǿ)=2τ/[σ(x) – σ(y)].
Q. If a body is subjected to stresses in xy plane with stresses of 60N/mm² and 80N/mm² acting along x and y axes respectively. Also the shear stress acting is 20N/mm². Find the maximum normal stress.
A. 90
B. 9Q.4
C. 9Q.2
D. 96
.
Answer: B
Explanation: σ=[σ(x) +σ(y)]/2 + √( [σ(x)-σ(y) ]²/2² + τ²).
Q. If a body is subjected to stresses in xy plane with stresses of 60N/mm² and 80N/mm² acting along x and y axes respectively. Also the shear stress acting is 20N/mm². Find the minimum normal stress.
A. 4Q.4
B. 4Q.6
C. 4Q.2
D. 50.6
.
Answer: B
Explanation: σ=[σ(x) +σ(y)]/2 – √( [σ(x)-σ(y) ]²/2² + τ²).
Q. If compressive yield stress and tensile yield stress are equivalent, then region of safety from maximum principal stress theory is of which shape?
A. Rectangle
B. Square
C. Circle
D. Ellipse
.
Answer: B
Explanation: The equation of four lines is given by σ1=± S(yt), σ2=±S(yC. Now given S(yt)=S(yC., hence the region of safety is of square shape.
Q. Maximum Principal Stress Theory is not good for brittle materials.
A. True
B. False
.
Answer: B
Explanation: Experimental investigations have shown that maximum principle stress theory gives good results for brittle materials.
Q. The region of safety in maximum shear stress theory contains which of the given shape
A. Hexagon
B. Rectangle
C. Square
D. None of the mentioned
.
Answer: A
Explanation: In maximum shear stress theory we have the following equations: σ1= ±S(yt)
σ2= ±S (yt), σ1 – σ2 =±S (yt) assuming S(yt)=S(yC..
Q. How many classes of levers are there?
A. 2
B. 3
C. 4
D. 5
.
Answer: B
Explanation: The three classes are Fulcrum in the middle, Resistance in the middle and Effort in the middle.
Q. A bottle opener belongs to which class of the levers.
A. Effort in the middle
B. Fulcrum in the middle
C. Resistance in the middle
D. None of the mentioned
.
Answer: C
Explanation: In a bottle opener fulcrum can be considered at the end and resistance in middle as the actual work is done on the bottle cap which lies in middle of opener.
Q. Fulcrum can be located at one end of the lever.
A. True
B. False
.
Answer: A
Explanation: Fulcrum can be located in middle or at one end of the lever.
