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''.
Friction is the force which resists the relation motion between two surfaces in (mechanical) contact. It dissipates energy or power in various moving parts of machines & causes irreversibility in various processes. However, it is useful in various situations. Friction enables use to move on a surface or plane.