Which term describes the tendency of an object to remain at rest or in motion?

The correct term that describes the tendency of an object to remain at rest or in motion is inertia. Inertia is a fundamental concept in physics, particularly in Newton's first law of motion, which states that an object will not change its state of motion unless acted upon by a net external force. This means that an object at rest will stay at rest, and an object in motion will continue moving in a straight line at a constant speed unless a force causes it to change that motion.

The other terms provided have distinct meanings that do not accurately capture the specific characteristic of resistance to changes in motion. Propulsion refers to the action or process of pushing or driving something forward, often associated with engines or thrust. Momentum is the product of an object's mass and velocity, representing its motion and the effect it has when in motion but does not define the property of resistance to change. Velocity describes the speed of an object in a given direction, focusing on how fast it is traveling rather than its tendency to maintain its state of rest or motion.