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 a force, and it tries to prevent objects from moving. Friction has benefits as well as negative consequences. This force exists in all mechanical objects where two or more moving parts have contact with each other. This causes parts to break down quickly unless a lubricant is used to reduce the friction.