The first regime includes dry granite up to at least 845 and wet granite below 250 c.
Coefficient of friction granite on granite.
Direct shear tests were conducted on a granite to granite interface for the purpose of tracing the evolution of frictional resistance as the initially smooth and polished surface wears during continuing shearing displacement.
First you tape the low g accelerometer on the end of the surface in this case a slab of granite.
At the moment when sliding on the freshly manufactured interface starts first slip the friction angle is very low between 15 and 20 but then it increases with.
The coefficients of friction are independent of the surface area in contact.
Static coefficient of friction.
The friction force is the force exerted by a surface when an object moves across it or makes an effort to move across it.
The static friction coefficient μ between two solid surfaces is defined as the ratio of the tangential force f required to produce sliding divided by the normal force between the surfaces n μ f n.
μ static μ s or kinetic μ k frictional coefficient.
The coefficient of kinetic friction is generally lower than the coefficient of static friction on the same surface.
The second regime includes wet granite above 350 c.
The frictional force can be expressed as.
For ground surfaces μ reaches a maximum after about 0 1 cm and then decreases to nearly a constant value after 0 5 cm of sliding has occurred.
F f frictional force n lb.
N normal force between the surfaces n lb there are at least two types of friction forces.
In this regime the coefficient of friction is high μ 0 7 to 0 8 and depends only modestly on temperature slip rate and p h 2 o.