NETA Personal Trainer Practice Exam

What is the effect of an unbalanced force on an object in motion, according to Newton's laws?

1. It stops the object

2. It changes the object's direction or speed

3. It has no effect on the object

4. It leads to constant acceleration

The correct answer is: It changes the object's direction or speed

An unbalanced force acting on an object in motion results in a change in the object’s direction or speed, which aligns with Newton's Second Law of Motion. According to this law, the acceleration of an object is produced when a net force acts on it, directly proportional to the magnitude of the net force and inversely proportional to the mass of the object. This means that an unbalanced force—one that is not canceled out by other forces—will cause the object to accelerate in the direction of that force. This acceleration can manifest as a change in speed (either speeding up or slowing down) or a change in the direction of motion. In contrast, when an unbalanced force is absent, other scenarios arise. An object in motion would either continue moving at a constant speed in a straight line without any net force acting on it, or if forces are balanced, there would be no change in motion at all. Therefore, while the idea of stopping an object (first choice) or having no effect (third choice) might seem plausible, they contradict the fundamental principles laid out by Newton. Additionally, while constant acceleration (fourth choice) can occur with a consistent unbalanced force applied, it doesn't encompass all possible outcomes of an unbalanced force