Describe how friction can be measured.
Answers
The force of friction occurs when one not ideally smooth object slides against another one. This force always directed against the movement and, in absence of other forces, slows down the sliding.
The force of friction depends, mainly, on two factors: material the objects are made of (more or less smooth) and how tightly they are pushed against each other. Typical textbook problem in physics is to determine the force of friction when one object (say, a wooden block) slides horizontally across some surface (like a table) and it's pushed against this surface by its weight (force of gravity). A variation is a similar problem, but the surface is not horizontal, but is a slope of some angle.Now, knowing the pressure
F
p
from the physical composition of an experiment and the coefficient of friction
μ
f
of materials involved, we can calculate the force of friction
F
f
as their product:
F
f
=
μ
f
⋅
F
p