Final answer:
Mahina's experience of dropping her books demonstrates the effects of Earth's gravitational pull. Gravity is the force that attracts masses towards each other, and every object with mass creates a gravitational field that exerts this force.
Step-by-step explanation:
Mahina was asked by her high school physics teacher to define gravity and share an experience that illustrates its effects. To answer the teacher's question, Mahina recalled her personal experience of when she dropped her books, which is a reflection of Earth's gravitational pull.
Gravity is a force that attracts two bodies with mass towards each other. On Earth, this force causes objects to fall towards the center of the planet. This gravitational force was first understood by Isaac Newton, who recognized that not only does Earth exert gravity, but the force extends to the Moon and is what keeps it and the planets in their orbits. According to Newton and later physics theories, every object with mass generates a gravitational field in space. An object placed within this field will experience a gravitational force, which is described mathematically as F = mg, where 'F' represents the gravitational force, 'm' is the object's mass, and 'g' is the gravitational field strength or acceleration due to gravity.
Experiences such as dropping a book illustrate the energy released due to gravity's pull. In the context of Mahina's experience, when she dropped her books, they accelerated toward the ground due to Earth's gravitational force acting upon them. Similar principles apply to a person jumping from a height, where both the person and Earth are subjected to mutual gravitational forces. However, due to Earth's much larger mass, it experiences an imperceptible change in momentum compared to the person who visibly moves towards the ground.