According to Newton's second law, what effect does a net (unbalanced) force have on an object?

• A. It keeps the object moving at constant velocity with no change in speed or direction.
• B. It causes the object to accelerate in the direction of the net force.
• C. It prevents any motion, so the object must remain at rest.
• D. It changes the object's mass but not its motion.

Answer: (B)

Verified step by step guidance

1. Recall Newton's second law of motion, which states that the net force acting on an object is equal to the mass of the object multiplied by its acceleration. Mathematically, this is expressed as \(\mathbf{F}_{\text{net}} = m \mathbf{a}\).
2. Understand that acceleration \(\mathbf{a}\) is the rate of change of velocity, which means it can change the speed, the direction, or both of the object's motion.
3. Recognize that if there is a net (unbalanced) force acting on an object, it cannot remain at constant velocity because acceleration implies a change in velocity.
4. Therefore, the net force causes the object to accelerate in the direction of the net force, changing its velocity accordingly.
5. Note that the object's mass remains constant in this context; the net force affects the motion, not the mass.