Which example best demonstrates how unbalanced forces change the speed of an object's motion? A) A child on a bicycle braking at
a stop sign. B) A child singing a song. C) A child sitting in a chair reading a book. Eliminate D) A child walking around the corner of a school hallway.
Unbalanced forces change the speed of movement of an object because they act non-uniformly on the object to which they relate. When a child on a bicycle brakes on a stop sign, the brakes act unevenly on the wheel, causing an uneven decrease in speed. In this way, you lose the balance of the movement you had prior to braking.
