An object moving in a straight line at a constant speed has a constant velocity; if a constant force is applied in the same direction, what happens?

An object moving in a straight line at a constant speed has a constant velocity; if a constant force is applied in the same direction, what happens?

• A. The object will continue moving in the same direction but will speed up
• B. It will stop immediately
• C. Its speed will stay the same but its direction will change
• D. It will move in the opposite direction

Answer: (A)

When a constant force acts in the same direction as the motion, it produces a constant forward acceleration. This acceleration adds to the existing velocity, so the object keeps moving in the same direction but speeds up over time. The direction doesn’t change because the force is not pulling backward or sideways; it’s aligned with the motion. If the force were opposite the motion, it could slow or reverse the object, and if it were perpendicular, it would change direction without altering speed in the same way.

When a constant force acts in the same direction as the motion, it produces a constant forward acceleration. This acceleration adds to the existing velocity, so the object keeps moving in the same direction but speeds up over time. The direction doesn’t change because the force is not pulling backward or sideways; it’s aligned with the motion. If the force were opposite the motion, it could slow or reverse the object, and if it were perpendicular, it would change direction without altering speed in the same way.