What term describes a push or pull that can change an object's motion?

• A. Energy
• B. Force
• C. Work
• D. Momentum

Answer: (B)

A force is a push or pull that can cause a change in an object's motion. In physics, forces are what make objects accelerate, following Newton's second law: the acceleration depends on the size and direction of the force and the object's mass. Forces can be pushes, like giving a nudge to a spinning door, or pulls, like gravity pulling a falling object, and they can act through contact or at a distance.

Energy describes the ability to do work or the capacity to cause change, but it isn’t the push or pull itself. Work is the transfer of energy that occurs when a force moves an object over a distance. Momentum is the quantity of motion (mass times velocity); a force changes momentum, but the term we're defining is the force itself—the cause of the motion change—not the motion or energy that results.