Principles of Tribology Mid - I, September - 2014

1.Wear per unit distance of sliding per contact point
  • πa2
Answer: A
2.The wear process are not always harmful since they can also be responsible for
  • Conventional process
  • unconventional process
  • Both 1 & 2
  • None
Answer: B
3.In modified theory of adhesion α value can be determined experimentally when s =
  • 4
  • 0
  • 2.33
  • 1
Answer: B
4.The friction between the two sliding surfaces depends on the absorbed layer is known as
  • Sliding friction
  • clean friction
  • Dry friction
  • boundary friction
Answer: B
5.The constant of proportionality μ defines the co-efficient of absolute viscosity gradient as uniform then  =
  • 0
  • 1
Answer: A
6.Reynolds equation can be derived from the
  • Navier-stokes equation
  • continuity equation
  • Both a & b
  • none of these
Answer: C
7.The graduation is based on the principal that the midpoint kinetic viscosity of each grade is __________ greater than the proceeding one
  • 40%
  • 50%
  • 60%
  • 70%
Answer: B
8.When the typical dry surfaces come in contact surfaces are high spots called as
  • Asperities
  • static friction
  • wear
  • none of these
Answer: A
9.For the boundary lubrication may be reduce the μ value to the order of_______ the question of wear will still remain
  • 10-1
  • 10-2
  • 10-3
  • 10-4
Answer: B
10.When the progressive loss of material from the mating surfaces of a pair bodies is known as
  • Friction
  • wear
  • lubrication
  • sliding friction
Answer: B
11.Abrasive wear is usually caused by _______________
Answer: Ploughing out
12.Due to excessive wear surface stress are generated due to ______________
Answer: Load or speed
13.The wear results in occurrence of small loose particles called ___________
Answer: Wear debris
14.In Modified theory of Adhesion Sm may be defined as ____________
Answer: Critical shear strength
15.Friction is commonly define as the _______________ to motion.
Answer: Resistance
16.In single Adhesion theory of friction force required to plough through the ___________
Answer: Hard asperities
17.The classification is based on viscosity value at ____________ for some grades also at various low temperatures.
Answer: 210°f (99°c)
18.Commonly used viscosity grades have been standardized as __________ & ___________
Answer: ISO & SAE
19.Bearings may be defined as any sort of connection between two machine parts in _____________
Answer: Relative motion
20.The force of kinetic friction is ___________ of the sliding velocity.
Answer: Independent