1 So i have the equation m d2xdt2c dxdtkx0 where d2xdt2 is the second derivative. That situation is described by Newtons Second Law of Motion. The external forces are the ones which act on a body and exist outsideexternal of the system of that body.
Newtons second law describes the affect of net force and mass upon the acceleration of an object.
The first law states that a body at rest tends to stay at rest and a body in motion tends to stay in motion at a constant speed in a straight line unless acted upon by a force. Newtons law of gravitation resembles Coulombs law of electrical forces which is used to calculate the magnitude of the electrical force arising between two charged bodies. Often expressed as the equation a Fnetm or rearranged to Fnetma the equation is probably the most important equation in all of Mechanics. The equation is commonly written as Fma.