I'm watching some Physics lectures on the internet by Leonard Susskind:
In this lecture, and also in Wikipedia and other places phase space is described as the space of all the states we need to know to determine the configuration of the system infinitely into the future.
But I don't understand how is position and velocity enough to determine this, what about forces?
Let's say we have a particle and we want to know where it will be in 10 seconds, we obviously need it's starting position, it's starting velocity and also all the forces acting on it, or it's acceleration.
Where is my misunderstanding?