The inertia of the rocket
Since there is no friction in outer space, stopping a moving rocket's engine does not stop it immediately. When the rocket's engine stops, the rocket continues to move forward according to the law of inertia. To stop the rocket, you have to emit something in the forward direction.
When a car is abruptly accelerated, drivers and passengers may feel as though their bodies are moving backward. In reality, inertia is making the body want to stay in place as the car moves forward.
A car that is moving will continue even if you switch the engine off.
In a condition where no force is applied to an object, a stationary object tries to stay stationary, and an object that is moving attempts to continue to move.
This inertia is prominent in the absence of friction interference. Space is a very good inertial system in this regard.