MCQ
28181. An ideal machine is one whose efficiency is- [BREB-15]
ব্যাখ্যা: The machine whose efficiency is 100% and in which friction is totally absent or Zero, is called as ideal machine. = 100%
between 60 and 70%
between 70 and 80%
between 80 and 90%
100%
28182. The unit of power in S.I. unit is-[MES-18]
The unit of power is watt. The unit of energy is joule.
horsepower
kg.m
joule
watt
28183. 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
28184. The terms 'leverage' & 'mechanical advantage' of a compound lever have got same meaning-----
Right
Wrong
28185. The friction experienced by a body, when at rest, is known as- (BREB-15]
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.
static friction
coefficient of friction
dynamic friction
limiting friction
28186. The resultant of two forces P & Q is R. If Q is doubled, the new resultant is perpendicular to P. Then-
P=Q
Q=R
Q=2R
none of these
28187. The term 'force' may be defined as an agent which produces or tends to produce, destroys or tends to destroy motion.
Agree
Disagree
28188. A force while acting on a body may-
Change its motion
Balance the force
Internal stress rise
All of this
28189. The process of finding out the resultant force is called -----of force.
Composition
Resolution
28190. The unit of strain is- (BADC-18)
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
mm
N/mm
N-mm
no unit
None
28191. The energy stored in a body when strained within elastic limit is known as- [MES-18]
resilience
strain energy
impact energy
proof resilience
28192. Hook's law holds good up to ----[BADC 18]
elastic limit
breaking point
plastic limit
yeild point
none
28193. The angles between two forces when the resultant is maximum & minimum respectively are-
0° & 180°
180° & 0°
90° & 180°
90° & 0°
28194. 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)
28195. The resultant of two equal force P making an angle θ, is given by-
2P sinθ/2
2P cosθ/2
2P tanθ/2
2P cot-θ/2
28196. Two forces are acting at an angle of 120°. The bigger force is 40N and the resultant is perpendicular to the smaller one. The smaller force is-
20N
40N
80N
none of this
28197. Whenever a material is loaded within elastic limit, stress is-strain. [BREB-15]
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.
equal to
directly proportional to
inversely proportional to
None of these
28198. 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
28199. Which is not a unit of stress? [MES-16]
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).
Pa
N
psi
MPa
28200. 1kg force is equal to-
7.8N
12N
8.91 N
9.81N