For simplicity we will say that the forces acting on the rocket are thrust and gravity. Therefore,
where R is the rate of fuel consumption, u is the velocity of the gasses with respect to the rocket, m is the mass of the rocket, and g is the gravitational acceleration of the earth.
This equation was derived for velocity in space. We will assume that the velocity on earth is close to this.
vf=-uln(mf/mi) + v0
Momentum is mostly used for collisions so if you want to know what would happen if a rocket hit you while it was moving...
The escape velocity is the velocity that a ballistic projectile needs in order to break away from the Earth's gravitational pull. Its value is