Is time really necessary? In classical mechanics the coordinates of a particle are functions of time. That path is a solution of the equations of motion. In principle then it is just a parameter and can be eliminated giving a direct relation between the coordinates E.g. If you do this for a particle subject to uniform downward acceleration you obtain the upside down parabolic relation of x with y. No time.
 So is time really necessary?
 A: While some equations that contain an explicit time coordinate could be reformulated in a way that doesn't explicitly reference time, I believe this is missing the broader point about why time matters.  Arguably, the purpose of physics (and science more generally) is to create a framework by which we can understand, and make testable predictions about, the physical world.  We, as humans, care about when things will happen, and so we often want our predictions to include a component of "when".  Moreover, the information available to us is often the state of things at a certain time (i.e., the initial conditions), which introduces time into the problem.
If I throw a ball in the air, I don't just want to know what path it will follow - I want to know when it's coming back down.  Wouldn't you?
A: Take a three dimensional map. If all the derivatives (dx/dy, dy/dz, dz/dx) were zero it would just be a flat land with no information. Without time even nonzero derivatives have a unique information  fixed for ever on this map,  life cannot be described, as  no change ever. Introducing a dx/dt, etc allows for changes in the map including finally life.
