What is the outcome of a net force acting on an object?

• A. It can change the object's speed, direction of motion, or both.
• B. It must be at rest.
• C. It changes nothing about motion.
• D. It always speeds up.

Answer: (A)

A net force on an object produces acceleration, and acceleration changes the object's velocity. The speed can rise if the force points in the same direction as the motion, or fall if it points opposite, and the velocity can change direction if the force has a component that redirects the motion. In other words, the net force determines how the velocity vector changes—speed, direction, or both. The object doesn’t have to be at rest, and the net force doesn’t always speed things up; it can slow them down or alter the path as well.