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1.0.0
MCQ
27081. The poisson's ratio for steel varies from- [BREB-17; MES-18]
0.22 to 0.27
0.32 to 0.42
0.25 to 0.33
0.31 to 0.34
ব্যাখ্যা: Poisson's ratio values for different materiais. Material Possion's ratio Clay 0.30-0.45 Stainless steel 0.30-0.31 Steel (MS) 0.27-0.30 Castiron 0.21-0.26
27082. An ideal machine is one whose efficiency is- [BREB-15]
between 60 and 70%
between 70 and 80%
between 80 and 90%
100%
ব্যাখ্যা: The machine whose efficiency is 100% and in which friction is totally absent or Zero, is called as ideal machine. = 100%
27083. The term 'force' may be defined as an agent which produces or tends to produce, destroys or tends to destroy motion.
Agree
Disagree
27084. The relation between Young's modulus (E) and Bulk modulus (K) is given by- [MES-18]
K=3m-2 /mE
K= mE/3(m-2)
K=3(m-2)/mE
K= mE / 3(m-2)
27085. If the resultant of two equal force has the same magnitude as either of the force, then the angle between the two forces is- [BADC-18]
30°
120°
60°
90°
ব্যাখ্যা: Let the two forces be found F₂ at an angle x where IF₁I =I F₂I = IRI We know, Resultant force, R^2 = P² + Q^2+2PQcos0 F₁ ^2= F₁ ^2 + F₁ ^2+2 F₁ ^2cos0 F₁ ^2=2 F₁ ^2(1+cos0) Cancelling F₁ ^2 on both sides 1=2(1+cos0) Cos0 = 1/2 0=120°
27086. Two parallel sides of a trapezium are a and b, its height is h, its CG from base is at--- [MES-16]
π(a+b)/3h
h/3 (b+2a/b+a)
3/8(b+a /a+2b)
2h/3 b+2a/b+a
27087. The ratio of linear stress to linear strain is --[MES-18,BADC-18]
bulk modulus
modulus of rigidity
poisson's ratio
modulus of elasticity
none
27088. A force while acting on a body may-
Change its motion
Balance the force
Internal stress rise
All of this
27089. The unit of moment of inertia of an area is-[ IMES-18]
kg.m²
kg/m²
kg.m² s
m^4
ব্যাখ্যা: Moment of intertia, Ad^2= (mxm)x m^2= m^4
27090. The unit of power in S.I. unit is-[MES-18]
horsepower
kg.m
joule
watt
The unit of power is watt. The unit of energy is joule.
27091. Hook's law holds good up to ----[BADC 18]
elastic limit
breaking point
plastic limit
yeild point
none
27092. Young's modulus is the property of- [PPA-19]
Gas only
Solid only
Liquid and solid
Liquid only
ব্যাখ্যা: Young's modulus is a mechanical property that measures the stiffness of a solid material.
27093. The unit of strain is- (BADC-18)
mm
N/mm
N-mm
no unit
None
Strain is defined as "deformation of a solid due to stress. Strain is a dimensionless unit since it is the ratio of two lengths. strain= change in length/original length
27094. Which is not a unit of stress? [MES-16]
Pa
N
psi
MPa
Stress is a force that tends to deform the body on which it acts per unit area. It is measured in N/m² and this unit is specifically called pascal (Pa). Unit of stress N/m², Pa, MPa, Psi Unit of force =N (Newton).
27095. The energy stored in a body when strained within elastic limit is known as- [MES-18]
resilience
strain energy
impact energy
proof resilience
27096. The stress developed in the material without any permanent set is called. [MES-18]
elastic limit
breaking point
yield point
ultimate point
ব্যাখ্যা: Elastic limit, maximum stress or force per unit area within a solid material that can arise before the onset of permanent deformation.
27097. The ultimate tensile stress for mild steel is - the ultimate compressive stress. [MES-18]
equal to
more than
less than
none of these
ব্যাখ্যা: The ultimate tensile stress of mild steel is more than the ultimate compressive stress. Young modulus of a wire will be equal to stress for unit strain.
27098. 1kg force is equal to-
7.8N
12N
8.91 N
9.81N
27099. The friction experienced by a body, when at rest, is known as- (BREB-15]
static friction
coefficient of friction
dynamic friction
limiting friction
ব্যাখ্যা: Static friction is the force of friction experienced by a body when it is at rest it is the value of the limiting friction just be fore slipping occurs.
27100. Whenever a material is loaded within elastic limit, stress is-strain. [BREB-15]
equal to
directly proportional to
inversely proportional to
None of these
ব্যাখ্যা: Hook's law states that strain is directly proportional to strain produced by the stress when a material is loaded within the elastic limit.