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 that acts against a moving object to slow it down. A type of friction is air resistance. Friction opposes the direction in which the object is moving, causing the object to decrease in speed, or stop all together. All kinds of friction cause moving objects to slow down or stop. Friction can be quantified as a force resisting motion which is proportional to the weight of the object, for an object lying on a flat surface. The frictional force is found by multiplying the objects weight by a coefficient of friction, which is usually less than one, but can be higher than one (for example with rubber tyres on dry tarmac).