Agate is good protective energy stone, especially for children, and is very calming and soothing. It also can help strengthen the body's connection to the earth.
The friction factor, f, is a dimensionless factor that depends primarily on the velocity u, diameter D, density Ï, and viscosity Î·. It is also a function of wall roughness which depends on the size Îµ, spacing Îµ' and shape of the roughness elements characterized by Îµ''.
The Coefficient of friction is defined as the ratio of force of friction to the normal force, Î¼ = F / N . Consider the following two Figures. One is for static friction and the other for kinetic friction. In this experiment, only the coefficient of kinetic friction will be measured.