Newton's Laws — Set 3

Correct Answer: C. Centripetal Force

Centripetal force is the net force that acts toward the center of the circular path. According to the Second Law, this force is necessary to constantly change the direction of the object. Without this force, the object would travel in a straight line due to inertia.

Correct Answer: C. mg

Weight is the force of gravity acting on an object, calculated as the product of mass and 'g'. While mass is constant everywhere, weight changes depending on the local gravitational field. On Earth, 'g' is approximately 9.8 meters per second squared.

Correct Answer: A. First Law

The First Law qualitatively defines force as an agent that changes the state of rest or motion. It establishes that without such an agent, motion remains uniform. The Second Law then provides the quantitative formula for calculating that force.

Correct Answer: B. Both Momentum and Kinetic Energy

In an ideal elastic collision, both the total linear momentum and total kinetic energy remain constant. Real-world collisions are often inelastic, where some kinetic energy is lost to heat or sound. However, total momentum is conserved in all closed-system collisions.

Correct Answer: D. They are equal

Newton's Third Law states that action and reaction forces are always equal in magnitude. They occur simultaneously and act in exactly opposite directions. Despite having equal force, they may produce different accelerations if the objects have different masses.

Correct Answer: C. Inertia

Inertia is the inherent tendency of an object to resist changes to its current state of motion. It is the reason why objects don't start or stop moving spontaneously. This concept is the central theme of Newton's First Law of motion.

Correct Answer: A. 1 m/s²

Using F = ma, 1 Newton divided by 1 kilogram results in an acceleration of 1 m/s². This is the fundamental definition of the unit 'Newton'. It provides a simple benchmark for understanding force-mass-acceleration interactions.

Correct Answer: C. Third Law

The correct answer is 'Third Law'. When walking, a person pushes the ground backward (action), and the ground pushes the person forward (reaction). The frictional force from the ground provides the necessary reaction to move forward. Without friction, walking would be impossible as seen on smooth ice.

Correct Answer: D. Force

Force is a vector quantity because it possesses both magnitude and a specific direction. Scalar quantities like mass and speed only have magnitude. Vector addition rules must be followed when multiple forces act on a single object.

Correct Answer: A. No reaction force can be generated

Walking requires pushing against the ground to generate a forward reaction force. On a frictionless surface, there is no grip to apply the backward action force. Consequently, the Third Law cannot facilitate forward propulsion in this environment.