A pendulum released from a height swings upward to a lower height. This demonstrates which law of motion?

The correct answer demonstrates the concept of conservation of energy rather than the first law of motion. When a pendulum is released from a height, it converts its potential energy at the highest point into kinetic energy as it swings down. Upon reaching the lowest point, the kinetic energy begins to convert back into potential energy as the pendulum swings upward again.

As the pendulum reaches its new height, it does not rise to the original height due to energy lost to friction and air resistance. This scenario highlights the transformation and conservation principles of energy, showing that while energy may change forms, the total energy in a closed system remains constant, barring external losses.

The first law of motion, which states that an object in motion will stay in motion unless acted upon by an external force, primarily addresses the concept of inertia and does not directly apply to the energy transformations occurring in this pendulum scenario. The second law of motion relates to the relationship between force, mass, and acceleration, while the third law of motion focuses on action-reaction forces.