Which statement about balanced forces is true?

• A. They produce acceleration.
• B. They cause no change in motion.
• C. They always move objects upward.
• D. They increase speed indefinitely.

Answer: (B)

Balanced forces cancel each other out, giving a net force of zero. When the net force on an object is zero, there is no acceleration, so the object's motion doesn't change. If something is at rest, it stays at rest; if something is moving, it keeps moving at the same speed and in the same direction.

For example, a book resting on a table has gravity pulling down and the table pushing up with equal force, so it stays still. A car cruising at constant speed has forward thrust balanced by backward drag and friction, so its speed and direction stay the same.

Because there is no net force, balanced forces do not cause acceleration, do not make objects move upward, and do not cause speed to increase indefinitely. Therefore, they result in no change in motion.