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Strength of Materials MCQs Dams Stability Analysis
To ensure economy in dam sections, the ______ should be minimum.
a) Base width
b) Top width
c) Spillway length
d) Toe of the wall
View Answer
Answer: a
Explanation: In dams, the economy prevails if the cross section of a dam is provided with minimum base width. Base width “b” can be determined from the equation: b2 +ab+ a2 = H2/ S.
Calculate the maximum stress at the base section is the self weight is 4400 kN. The top and bottom width of them are 3 and 8 m respectively. Take (e) = 2.97.
a) 1658.15 kN/m2
b) 1775.12 kN/m2
c) 1897.45 kN/m2
d) 2336.67 kN/m2
View Answer
Answer: b
Explanation: The maximum stress at the base section = W/b (1+6e/b)
P= 4400/8 (1+6×2.97/8)
= 1775.125 kN/m2.
If the maximum stress is positive, then the nature of stress is ____
a) Tensile
b) Shearing
c) Compressive
d) Bending
View Answer
Answer: c
Explanation: If the stress developed in the dam section at the base is positive there it indicates the nature of stress to be compressive.
Determine the eccentricity of the dam section, if the base width of the dam be 6m. Take Z = 5.5m.
a) 2.5
b) 1.5
c) 3.5
d) 4.5
View Answer
Answer: a
Explanation: e = Z – b/2. [The value of Z = 5.5m] = 5.5 – 6/2
= 5.5 – 3
= 2.5 m.
Calculate the minimum stress developed at the heel of the dam, if the self weight of the dam is 924 kN and the base with is 6 metres [Take e = 0.0945m].
a) 145 kN/m2
b) 139 kN/m2
c) 167 kN/m2
d) 183 kN/m2
View Answer
Answer: b
Explanation: The minimum stress developed at the heel of the dam is W/b ×(1-6e/b).
= 920/6 ×(1-6×0.0945/6).
= 139 kN/m2.
The side slopes depend on ____________ conditions of a proposed dam.
a) Toe width
b) Height of foundation
c) Character of material
d) Free board allowance
View Answer
Answer: c
Explanation: The upstream and downstream slopes of the Dam should be stable in all situations the side slopes depend upon
1.Height of the dam
2.Character of material
3.Nature of foundation.
Molitor’s formula can be used for calculation of ___________
a) Freeboard
b) Toe width
c) Wave height
d) Base drop
View Answer
Answer: c
Explanation: The minimum height of the free board for wave action is generally taken to be equal to 1.5 hw. Where hw = height of wave action.
It can be calculated using 0.032(VF)1/2.
The height of the dam = free board + ___________
a) FTL
b) MWL
c) FRL
d) HFL
View Answer
Answer: d
Explanation: The dam’s height mainly depends on HFL of the reservoir. The height of the dam above surface is given by the HFL plus the free board.
Height of the dam = HFL + free board.
_____________ sections allow the surplus discharge to flow in dams.
a) Mulching
b) Over reinforced
c) Breaching
d) Balanced
View Answer
Answer: c
Explanation: Sometimes during construction, the surplus works are avoided in many tanks. In such circumstances, breaching sections are provided in the dams to allow the surplus flood discharge. With this the scouring of section can be avoided.
If the minimum stress developed is negative, then the nature of stress is ___________
a) Shearing
b) Tensile
c) Bending
d) Compressive
View Answer
Answer: b
Explanation: If the minimum stress developed at the base of the dam section is negative, then the respective nature of the stress will be in tensile condition.
____________ creates concentrated seepage in dams section.
a) Longitudinal cracks
b) Transverse cracks
c) Construction cracks
d) Contraction cracks
View Answer
Answer: b
Explanation: Due to differential settlement cracks may be developed in the bund. These are of two types 1) longitudinal cracks 2) transverse cracks. The transverse cracks are more dangerous to the dam section because they can create concentrated seepage.
The upstream slope recommended for sand and gravel with RCC core wall is __________
a) 1:2
b) 3:1
c) 2.5:1
d) 1.5:1
View Answer
Answer: c
Explanation: According to Terazghi, the following upstream slopes should be recommended.
For:
1. Homogeneous well graded – 2.5 : 1
2. Homogeneous coarse silt – 3 : 1
3. Sand and gravel with RCC core wall – 2.5 : 1.
Major distributaries discharge varies from ____________
a) 0.25 to 5 cumecs
b) 2 to 4 cumecs
c) 1.5 to 5 cumecs
d) 1.2 to 5 cumecs
View Answer
Answer: a
Explanation: The major distributary takes off from a branch canal to distribute the water to various parts of the field. The supply of the water varies from 0.25 to 5 cumecs.
Field channels are also known as ______
a) Branch canals
b) Slope channels
c) Water courses
d) Contour canals
View Answer
Answer: c
Explanation: The water courses are the channel that carries irrigation water to the fields. The water courses derive their supply from distributaries through outlets. They are also called as field channels.
The structures constructed along are distributaries are called as _______
a) Inlets
b) Outlets
c) Distributaries
d) Channels
View Answer
Answer: b
Explanation: An outlet is a simple and small irrigation structure which is constructed along the distributaries. The amount of water that is withdrawn through the outlet is in proportion to the area that is irrigated below respective point.
Strength of Materials MCQs Slope
Slope in the beam at any point is measured in ____________
a) Degrees
b) Minutes
c) Radians
d) Metric tonnes
View Answer
Answer: c
Explanation: The slope is defined as at any point on the bent beam is the angle measured in terms of radians to which the tangent at that point makes with the x axis.
Elastic curve is also known as __________
a) Refraction curve
b) Reflection curve
c) Deflection curve
d) Random curve
View Answer
Answer: c
Explanation: An elastic curve is defined as the line to which the longitudinal axis of a beam deviates under given load. It is also called a deflection curve.
Which of the following method is not used for determining slope and deflection at a point?
a) Moment area method
b) Double integration method
c) Isoheytal method
d) Macaulay’s method
View Answer
Answer: c
Explanation: The method “Isoheytal” can be used for calculating run-off over an area. The remaining methods are effectively adopted to calculate the slope and deflection at a point in any type of beam.
The slope is denoted by _______
a) k
b) y
c) i
d) c
View Answer
Answer: c
Explanation: The slope at any section in a deflection beam is defined as the angle measured in radians to the tangent at the section makes with the original axis of the beam.
•It is denoted by “i”.
Calculate the slope at supports, if the area is 180kNm2. Take flexural rigidity as 50000.
a) 0.0054 radians
b) 0.0072 radians
c) 0.0036 radians
d) 0.108 radians
View Answer
Answer: c
Explanation: Maximum slope at supports be i = A/EI
= 180/50000
i = 0.0036 radians.
In cantilever beams, the slope is _____________ at fixed end.
a) Maximum
b) Zero
c) Minimum
d) Uniform
View Answer
Answer: b
Explanation: The slope in cantilever beam is zero at the fixed end of the cantilever and the slope is maximum at it’s free end. The slope is determined in the moment area method through Mohr’s theorems.
Slope is maximum at _______ in simply supported beams.
a) Mid span
b) Through out
c) Supports
d) At point of loading
View Answer
Answer: a
Explanation: In case simply supported beams, the slope is maximum at the end supports of the beam and relatively zero at midspan of a symmetrically loaded beam.
Mohr’s theorem- 1 states ________
a) E/AI
b) I/EA
c) A/EI
d) A=EI
View Answer
Answer: c
Explanation: According to Mohr’s theorem-1, the change of slope between any of the two points on and Elastic axis is equal to the net area of bending moment diagram (A) between these two points divided by flexural rigidity(EI).
Using Mohr’s theorem, calculate the maximum slope of a cantilever beam if the bending moment area diagram is 90kNm2. Take EI = 4000 kNm2.
a) 0.0225 radians
b) 0 0367 radians
c) 0.0455 radians
d) 0.066 radians
View Answer
Answer: a
Explanation: The maximum slope at free support (in cantilever beam) = i = A/EI
= 90/4000
= 0.0225 radians.
Contour canals are also called as ______
a) Single bank canal
b) Ridge canal
c) Side slope canal
d) Watershed canal
View Answer
Answer: a
Explanation: In this method, the canal is aligned along the falling contour. A generally higher side is left without bank. So it is also called a single bank canal. The contour canal cuts across the natural drainage courses.
______________ provides employment to the cultivators at the time of famine.
a) Productive canal
b) Link canal
c) Protective canal
d) Inundation canal
View Answer
Answer: c
Explanation: The construction of protective canals and their development may be started during summer in hence they provide employment to the farmers at the time of drought and famine. Protective canals are not remunerative as productive canals.
______________ bricks are used in the lining of blast furnaces.
a) Magnesia
b) Dolomite
c) Bauxite
d) Fly ash
View Answer
Answer: c
Explanation: Bauxite bricks contain nearly 75% of aluminium and it is mixed with fire clay 15 to 30% and added some water to mould. High alumina bricks are resistant to corrosion.
_____________ bricks are resistant to corrosion.
a) silica bricks
b) magnesia bricks
c) bauxite bricks
d) fire bricks
View Answer
Answer: c
Explanation: Bauxite bricks contain nearly 75% of aluminium and it is mixed with fire clay 15 to 30% and added some water to mould. High alumina bricks are resistant to corrosion.
_____________ bricks are used in the lining of electric furnace.
a) Frosterite
b) Spinel
c) Chrome
d) Basic
View Answer
Answer: b
Explanation: The spinal bricks belong to neutral bricks. The spinel bricks mainly consist of alumina and magnesia. These bricks are widely used in the lining of electric furnace.
The finished product after burning magnesite is named as ___________
a) Perillax
b) Hellyx
c) Pyrolytaex
d) Syrilax
View Answer
Answer: a
Explanation: The heating of magnesia bricks is continued in the same kiln after reaching the temperature of 1950°C, and then some amount of iron oxide is mixed. The finished product after burning magnesite is named as perillax.
Strength of Materials MCQs Deflection
Units of deflection are _____
a) kNm
b) kN/m
c) kN
d) m
View Answer
Answer: d
Explanation: The term “deflection” is defined as the transverse displacement of a point on any straight axis to the curved axis. It is expressed in metres (m).
Which of the following method is used to determine the slope and deflection at a point?
a) Arithmetic increase method
b) Mathematical curve setting
c) Macaulay’s method
d) Lacey’s method
View Answer
Answer: c
Explanation: Macaulay’s method was devised by Mr WH Macaulay.
Advantages:
i. Gives one continuous expression for bending moment
ii. Constants of integration can be found by using end conditions
iii. By using this method, slope and deflection at any section can be determined throughout the length of the beam.
Deflection is denoted by _______
a) i
b) y
c) h
d) e
View Answer
Answer: b
Explanation: The deflection of a point on the axis of the deflected beam is defined as the angle developed in radians with tangent at the section makes with the original axis of the beam.
In cantilever beams, the deflection is zero at ___________
a) Free and
b) Fixed end
c) At supports
d) Through out
View Answer
Answer: b
Explanation: The deflection in cantilever beam is always zero at the fixed end and deflection in the cantilever beam at the free end is maximum.
Mohr’s theorem -¡¡ states?
a) Ax/EI
b) A/Ex
c) A/EI
d) Ae=Ix
View Answer
Answer: a
Explanation: Mohr’s theorem -¡¡ states “the intercept taken on a vertical reference line of the tangent at any two points on an elastic line is equal to the moment of BMD between these points, about the reference line divided by flexural rigidity (EI).
Calculate the deflection if the slope is 0.0225 radians. Take the distance of centre of gravity of bending moment to free end as 2 metres.
a) 45mm
b) 35mm
c) 28mm
d) 49mm
View Answer
Answer: a
Explanation: The deflection at any point on the elastic curve equal to Ax/EI
But, we know that A/EI is already slope equation.
So, slope × (the distance of centre of gravity of bending moment to free end = 2m).
0.0225 × 2
0.045m ~ 45 mm.
In simply supported beams, deflection is zero at _________
a) Mid span
b) Supports
c) Through out
d) Point of action of load
View Answer
Answer: b
Explanation: The deflection is always zero at the supports and the deflection is maximum at the mid span of a symmetrically loaded simply supported beam.
Which of the following is not a cross drainage work?
a) Aqueduct
b) Level crossing
c) Head regulator
d) Super passage
View Answer
Answer: c
Explanation: The head regulator is one of the canal regulation works. It can control the entry of silt into the canal. It can be used as a metre for measuring the discharge. It can shut out river floods.
Tail escape is also called as ___________
a) Outlet
b) Cross regulator
c) Weir type escape
d) Surplus escape
View Answer
Answer: c
Explanation: The crest of the weir is fixed at canal FSL. When the water level rises above FSL, it is disposed of into the natural drain. Hence, the tale escape is also known as weir type escape.
The land where all the water comes from ___________
a) Ridge dam
b) Watershed
c) Meander
d) Groynes
View Answer
Answer: b
Explanation: A watershed can be defined as an interconnected area of land which receives the water from surrounding ridge tops and transports it to a common point such as a lake or stream. All lands and waterways can be found within one watershed or another.
____________ reduces storm water discharge.
a) Rain water harvesting
b) Water harvesting
c) Watershed
d) Watershed management
View Answer
Answer: b
Explanation: The water harvesting is defined as the process of capturing rain where it falls. The objectives of water harvesting are 1) To provide drinking water 2) To provide irrigation water 3) To increase groundwater recharge to reduce storm water discharge.
Which of the following is not a soil moisture conservation method?
a) Spreading manure
b) Crop rotation
c) Recharge to ground water
d) By mulches
View Answer
Answer: c
Explanation: The methods which are adopted for preserving the water in the soil from being lost are called as soil moisture conservation methods. The major part of the water is lost through evapotranspiration. The recharge to groundwater is one of the techniques in rainwater harvesting.
Nutrients like ca, mg, si, al, S, K are lost due to ____________
a) Soil erosion
b) Percolation
c) Water logging
d) Watershed
View Answer
Answer: b
Explanation: The percolation is defined as a downward movement of water through the soil due to the force of gravity. The rapid percolation of water results in loss of plant nutrients and makes the soil acidic.
Warabandi has been practiced in India for more than ____________ years.
a) 130 years
b) 125 years
c) 140 years
d) 145 years
View Answer
Answer: b
Explanation: Warabandi is a rotational method for allocation of the available water equally in an irrigation system. It provides continuous rotation of water generally lasts 7 days. It has been effectively practiced in India for more than 125 years.
Gold, Copper and lead are the examples of ______
a) Ductility
b) Creep
c) Plasticity
d) Malleability
View Answer
Answer: c
Explanation: Plasticity in the property of Material by which the material can undergo permanent deformation and fails to regain its original shape on removal of load. Examples are gold, lead, etc.