What defines a rocket's "thrust"?

A rocket's "thrust" is fundamentally defined as the force produced by its motor to propel the rocket upwards. Thrust is a critical aspect of rocketry as it determines the rocket's ability to overcome gravitational forces and achieve lift-off. Specifically, it is the reaction force generated when the rocket's engine expels gases at high speed in the opposite direction, according to Newton's Third Law of Motion: for every action, there is an equal and opposite reaction.

Understanding thrust is essential for rocketry, as it directly affects the rocket's acceleration and ability to reach its intended altitude. The other options do not accurately describe thrust; for instance, the weight of the rocket is an important factor in rocketry but is distinct from thrust. The launch angle influences the rocket's trajectory rather than the force that propels it, and the duration of motor operation relates to burn time rather than the force exerted at that moment. Each of these aspects plays a role in a rocket's performance, but they do not define thrust itself.