What does Newton's second law of motion state?

• A. An object will not change its state of motion unless acted upon by a net external force
• B. The acceleration of an object is proportional to the net force acting on it and inversely proportional to its mass
• C. For every action, there is a reaction of equal magnitude
• D. An object's mass determines its speed

Answer: (B)

Newton's second law of motion articulates a fundamental relationship between force, mass, and acceleration. It states that the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass. This can be encapsulated in the familiar equation ( F = ma ), where ( F ) represents the net force, ( m ) is the mass, and ( a ) is the acceleration.

This means that if a greater force is applied to an object, it will accelerate more; conversely, if the mass of the object increases while the applied force remains constant, the acceleration will decrease. This law quantitatively describes how the motion of an object changes in response to applied forces, making it a cornerstone of classical mechanics.

In contrast, the other statements pertain to different principles. The first option describes Newton's first law, emphasizing inertia, while the third option reflects Newton's third law, which pairs actions and reactions in interactions. The fourth option incorrectly suggests a direct relationship between mass and speed, oversimplifying the dynamics of motion and neglecting the influence of force.