Two forces acting on the rocket immediately after leaving the launching pad are:
- Thrust provided by burning fuel in an upward direction
- Gravitational force in a downward direction
In flight, a rocket is subjected to four forces; weight, thrust, and the aerodynamic forces, lift and drag. The magnitude of the weight depends on the mass of all the parts of the rocket. The thrust force normally acts along the longitudinal axis of the rocket and therefore acts through the centre of gravity.