Which statement correctly describes the effect of a net unbalanced force on an object's motion?

• A. It changes the object's motion
• B. It makes the object heavier
• C. It has no effect
• D. It changes the object's color

Answer: (A)

When there is a net unbalanced force, it changes how the object moves. The total forces don’t cancel, so they produce an acceleration that can start movement from rest, speed it up, slow it down, or bend its path. The size and direction of the change depend on the net force and the object's mass. For example, pushing a stationary cart makes it move; pushing in the same direction as its motion makes it go faster; pushing opposite slows it down; a sideways push can steer it. If forces balance, motion doesn’t change. Weight or color aren’t affected by this net force, so they don’t describe how motion changes.