LESSON 1

Question 1

-Tribology comes from the Greek
word

Answer 1

“tribos”

Question 2

what does tribos means?

Answer 2

rubbing

Question 3

Tribology

Answer 3

It focuses on friction, wear
and lubrication of interacting
surfaces.

Question 4

5,000 BC

Answer 4

early humans learned that by rubbing sticks they can produced fire

Question 5

3500

Answer 5

rolling motion required less effort than sliding , wheel was invented

Question 6

what year did Leonardo da Vinci
formulated 2 basic laws of friction?

Answer 6

1495

Question 7

What are the 2 laws of friction that Leonard made?

Answer 7

1. Friction is independent of contact area.
2. Friction is proportional to load.

Question 8

Who said that the cause of deformation and wear of surfaces is friction?

Answer 8

Guillaume Amontons

Question 9

What year did Guillame Amontons rediscovered the two basic laws?

Answer 9

1699

Question 10

Who said that moving friction was not dependent on speed or velocity?

Answer 10

Sir isaac Newton

Question 11

Who formulated the third law of friction?

Answer 11

Sir Isaac Newton

Question 12

What year did Phillip Bowen and David Tabor gave physical explanation for the observed laws of friction?

Answer 12

1950

Question 13

Who determined that the true area of contact, is avery small percentage of the apparent area?

Answer 13

Phillip Bowden and David Tabor

Question 14

As the normal force increases

Answer 14

more asperities came into contact and the average area of each asperity contact grows

Question 15

Who said the following? Amontons Law of Friction are the first quantitative description of tribological process. Attemps to explain these laws have been central to the development of tribology.

Answer 15

Bill Needelman

Question 16

In what year did the elucidation of hydrodynamic lubraication began in England?

Answer 16

1883

Question 17

Who did the elucidation of hydrodynamic lubrication in England?

Answer 17

Beauchamp Tower

Question 18

Who published a differential equation describing this pressure buildup of the oil in the narrowing conveging gap between journal bearing surfaces?

Answer 18

Osborne Reynolds

Question 19

In what year did Osborne Reynolds published a differential equation?

Answer 19

1886

Question 20

Who published the Stribeck curve?

Answer 20

Richard Stribeck

Question 21

What is a plot of frictionas it related to viscoscity, speed and load?

Answer 21

Stribeck curve

Question 22

When was the Stribeck cruve published?

Answer 22

1902

Question 23

What year did Arnold Sommerfeld refined the work into a formal theory of hydrodynami lubrication?

Answer 23

1905

Question 24

Who refined the work of Tower and Reynolds?

Answer 24

Arnold Sommerfeld

Question 25

It is the force that hinders or resist the relative motion of two contacting bodies.

Answer 25

friction

Question 26

What is the
friction present between
two or more objects that
are not moving with
respect to each other.

Answer 26

Static Friction

Question 27

What is the
friction present between
two or more objects that are
in motion with respect to
each other.

Answer 27

Kinetic Friction

Question 28

The magnitude of _____ is greater due to
the greater value of its
coefficient.

Answer 28

static friction

Question 29

The magnitude of the ______ is comparatively
lesser due to the low value of
its coefficient.

Answer 29

kinetic
friction

Question 30

The equation representing static friction is given by

Answer 30

Fs= μs N

Question 31

The equation representing
kinetic friction is given by

Answer 31

Fk = μk N

Question 32

takes place when an object rolls on the surface.

Answer 32

Rolling friction

Question 33

takes place when two surfaces are rubbed against each other.

Answer 33

Sliding Friction

Question 34

takes place due to the deformation of surfaces.

Answer 34

Rolling Friction

Question 35

takes place
due to interlocking between
microscopic surfaces.

Answer 35

Sliding friction

Question 36

is dependent on the radius of the rolling object, the depth to which the object can sink, and the toughness of the surface.

Answer 36

coefficient of rolling friction

Question 37

depends on the texture of the surface and temperature to a certain extent. It is independent of external factors.

Answer 37

coefficient of sliding friction

Question 38

Coefficient of sliding friction:

Answer 38

Fsl = μslN

Question 39

Coefficient of rolling friction

Answer 39

Fr = μrN

Question 40

-is a process removal of material from one or both two solid surfaces in solid state contact, occurring when these two solid surfaces are in sliding
or rolling motion together.

Answer 40

Wear

Question 41

-it is the progressive damage, involving material loss, which occurs on the surface of a component as a result of its motion relative to the adjacent
working parts.

Answer 41

Wear

Question 42

-occurs when a harder material is rubbing against a softer material.

Answer 42

Abrasive Wear

Question 43

-the impingement of solid particles, or small drops of liquid or gas on a solid surface cause wear what is known as erosion of materials and components.

Answer 43

Erosive Wear

Question 44

-two bodies sliding over or pressed into each other which promote the
material transfer from one to another.

Answer 44

Frictional Wear/ Adhesive Wear

Question 45

This gem cannot be polished without friction norman without trials

Answer 45

Confucius