Final answer:
Thrust reversers on an aircraft produce a propulsive force to help slow down the plane during landing, but this force is not as strong as the engine's full forward thrust. They are intended to supplement other braking mechanisms and can bring the aircraft to a complete stop, but are not the primary stopping force.
Step-by-step explanation:
The thrust reversers on an aircraft are designed to help slow down the plane during landing by producing a force that is opposite to the direction of the plane's forward motion. While the exact ratio of reverse thrust to forward thrust can vary depending on the aircraft model and the specific design of the engines, in general, reverse thrust is not as powerful as the engine's full forward thrust capability. The reason for this is that the reverse thrust is meant to be a supplemental braking mechanism, not the primary means of stopping the aircraft.
Jet engines are capable of maintaining reverse thrust long enough to bring the aircraft to a stop and even move it backward slightly, which would be indicated by a negative final velocity. However, in practice, thrust reversers are used in conjunction with other braking systems, such as wheel brakes and spoilers, to safely reduce the speed of an aircraft on a runway after touchdown. Hence, it's practical to understand that thrust reversers significantly reduce the final velocity, but they do not deliver the same level of force as the engine's full forward thrust.