where fs,k is either the static or kinetic friction force,
respectively, μs,k is the coefficient of static/kinetic friction,
and FN is the normal force. Students are therefore
taught that the only quantities that affect static
and kinetic friction are the nature of the two materials
that are in contact with each other and the force at
which the two surfaces press against one another. In
this paper we describe a relatively simple experiment
that can be done to test the effect surface temperature
has on kinetic friction, and that depending on the
materials being used, the coefficient of kinetic friction
does indeed increase as the surface temperature of one
of the materials increases. Because such effects are not
normally discussed in standard introductory physics
textbooks, this experiment could be used as a nice inquiry
activity in introductory physics courses.