Tribology Quesitons : Quiz 1 Can somebody please assist with the answers to thes

Question

Tribology Quesitons : Quiz 1

Can somebody please assist with the answers to theses?

QUESTION 1 The viscosity index,
(a) is a measure of oil viscosity that ranges between 0 and 100;
(b) is higher for lubricants exhibiting greater change of viscosity with changing temperature;
(c) is negative for engine oils exhibiting increasing viscosity with increasing temperature;
(d) is higher for oils exhibiting less change of viscosity with changing temperature.
QUESTION 2 A base oil,
(a) is the minor component of an oil-based lubricant;
(b) is an oil additive that counteracts oil acidity arising from oil degradation;
(c) can be mineral, synthetic or biological in origin and constitutes the major component of a
lubricant;
(d) is a reference oil used for baseline comparisons.
QUESTION 3 Which one of the following is classed as a metal detergent typically used in
engine oils?
(a) Zinc dialkyldithiophosphate;
(b) Calcium salicyclate;
(c) Molybdenum disulfide;
(d) Lauric acid.
QUESTION 4 Viscosity increase of engine oils during service is most likely to be caused
by,
(a) fuel contamination;
(b) additive reaction;
(c) oil oxidation;
(d) dust contamination.
QUESTION 5 Which NLGI class grease would be considered most suitable for lubricating
the components of a conveyor station using an automatic centralised
lubrication system,
(a) 000;
(b) 1;
(c) 5;
(d) 10.   
QUESTION 6 Hydrodynamic lubrication requires,
(a) a converging film profile;
(b) an inviscid fluid;
(c) a negative entraining velocity;
(d) all of the above.
QUESTION 7 For a narrow journal bearing, an eccentricity ratio of about 0.7,
(a) gives maximum bearing load carrying capacity;
(b) gives minimum bearing friction;
(c) gives minimum bearing vibration;
(d) gives minimum bearing temperature rise.
QUESTION 8 The film thickness in EHL is,
(a) directly proportional to the entraining velocity;
(b) decreases as the reduced radius is increased;
(c) is theoretically zero if the surfaces are travelling at the same speed but in opposite
directions;
(d) increases as the elastic moduli of the contacting surfaces increases.
QUESTION 9 The major mechanism of friction reduction in boundary lubrication
involves,
(a) increasing the hardness of the surface oxide;
(b) weakening of the surface material;
(c) increasing the yield strength of the surface material;
(d) suppressing adhesion between contact interfaces.
QUESTION 10 An elastomer seal slides against the steel shaft of a hydraulic linear actuator.
What coating would be preferred to reduce both friction and wear in an
environment contaminated by hard sand and dust particles?
(a) Titanium nitride on the seal;
(b) Titanium nitride on the shaft;
(c) Teflon on the seal;
(d) Teflon on the shaft.

Explanation / Answer

1. d

2. c

3. b

4. d

5. a

6. a

7. c

8.

9.

10.

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