To find the initial velocity of a rocket, you typically need to use the rocket equation. The rocket equation relates the mass of the rocket at any given time to its velocity. It takes into account the mass of the rocket, the mass of the propellant it carries, and the exhaust velocity of the propellant.
The rocket equation is expressed as follows:
Δv = ve * ln(m0 / mf)
Where: Δv is the change in velocity (which represents the initial velocity of the rocket), ve is the exhaust velocity of the propellant, m0 is the initial mass of the rocket (including the mass of the propellant), and mf is the final mass of the rocket (including the mass of any remaining propellant).
To use this equation, you'll need to know the exhaust velocity of the propellant and the initial and final masses of the rocket. The exhaust velocity depends on the type of propellant being used, and the initial and final masses can be determined by considering the mass of the rocket and the mass of the propellant it carries at the beginning and end of the propulsion phase.
It's important to note that the initial velocity calculated using the rocket equation represents the change in velocity achieved due to the propulsion system. It doesn't take into account factors like atmospheric drag or gravitational effects, which can also influence the actual velocity of a rocket during flight.