Which describes the thrust curve of a progressive motor?

The thrust curve of a progressive motor is characterized by a general increase in thrust during the burn. This type of motor is designed to provide a thrust profile that gradually builds as the propellant burns, allowing for a smooth acceleration of the rocket.

This behavior is advantageous in rocketry because it provides a more gentle initial ascent and gradually increases the rocket's speed, which can help in managing aerodynamic forces during flight. The progressive thrust helps reduce stress on the airframe and can lead to more stable flight characteristics overall.

In contrast, a decrease in thrust during burn would suggest a different type of motor behavior, typically found in motors designed for a consistent performance drop-off. A high constant thrust level signifies a motor that maintains thrust without any significant increase or decrease, not reflective of the progressive nature. An irregular thrust pattern would indicate a motor with unpredictable thrust behavior, which is not aligned with the defined function of a progressive motor.