Statics is the action of one body on another. A force is either a push or a pull. A force tends to move a body in the direction of its action. The action of a force is characterized by its magnitude, by the direction of its action, and by its point of application. Thus, force is a vector quantity, because its effect depends on the direction as well as on the magnitude of the action. Forces are classified as either contact or body forces. A contact force is produced by direct physical contact; an example is the force exerted on a
Order of magnitude <math>0.5, perhaps because the arithmetic mean of formula_5 and formula_12 approaches formula_13 for increasing formula_14. This definition has the effect of lowering the values of formula_4 slightly: Yet others restrict formula_10 to values where formula_17, making the order of magnitude of a number exactly equal to its exponent part in scientific notation. Orders of magnitude are used to make approximate comparisons. If numbers differ by one order of magnitude, "x" is "about" ten times different in quantity than "y". If values differ by two orders of magnitude, they differ by a factor of about 100. Two numbers of the same