LESSON 9: FRICTION

Question 1

Tangential forces generated between contacting surfaces

Answer 1

Frictional Forces

Question 2

A machine or process in which friction is small
enough to be neglected is said to be ____

Answer 2

ideal

Question 3

When friction must
be taken into account, the machine or process is termed _____

Answer 3

real

Question 4

Occurs when the unlubricated surfaces of two solids
are in contact under a condition of sliding or a tendency to
slide.

Answer 4

Dry Friction

Question 5

Dry Friction is also called ____

Answer 5

Coulomb friction

Question 6

The principles of dry or Coulomb friction were developed largely from the experiments of _____ in ____ and from the work of Morin from ____ to ____.

Answer 6

Coulomb
1781
Morin
1831, 1834

Question 7

Enumerate the 3 general types of friction

Answer 7

Dry friction, Fluid friction, Internal friction

Question 8

-After slippage occurs, a condition of ______
accompanies the ensuing motion. It is usually somewhat less than the maximum static friction force.

Answer 8

kinetic friction

Question 9

When the friction force reaches its limiting static value Fmax, the angle α reaches a ______ value Φs.

Answer 9

maximum

Question 10

-occurs when adjacent layers in a fluid (liquid or gas)
are moving at different velocities.

Answer 10

Fluid friction

Question 11

-occurs in all solid materials which are subjected to
cyclical loading.

Answer 11

Internal Friction