 The initial conditions are given by the "constant" values at ,

The solution to the equation of motion, with specified initial values, describes the system for all times after .Other dynamical variables like the momentum of the object, or quantities derived from and like angular momentum, can be used in place of as the quantity to solve for from some equation of motion, although the position of the object at time is by far the most sought-after quantity.Sometimes, the equation will be linear and is more likely to be exactly solvable.