If you could drill a hole straight through the Earth and drop an object into it, the object's behavior would be governed by the principles of gravitational attraction. Here's what would happen:
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Initial Fall: When you drop the object into the hole, it would initially accelerate downward due to Earth's gravity, which is strongest at the surface.
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Decreasing Gravity: As the object falls towards the center of the Earth, the force of gravity acting on it would decrease. This is because, according to the shell theorem, only the mass of Earth that is closer to the center than the object contributes to the gravitational pull. As the object approaches the center, the gravitational force decreases linearly, reaching zero at the center.
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At the Center: When the object reaches the exact center of the Earth, it would briefly experience zero gravitational force. However, it would not stop there…
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Inertia and Oscillation: Due to its inertia, the object would continue moving past the center and head towards the other side of the hole. It would slow down as it moves upward due to gravity, eventually coming to a stop at the surface on the opposite side.
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Return Trip: After reaching the opposite surface, the object would then fall back down into the hole due to gravity, repeating this oscillatory motion indefinitely (assuming no air resistance or other damping forces).
So, the correct statement from your options would be: The object would fall down from one side of the hole to the edge of the side and then fall back down to the start. This pattern would continue forever.
In reality, factors like air resistance and the heat and pressure at the center of the Earth would alter this idealized scenario, but in a theoretical, frictionless context, the object would indeed oscillate back and forth through the Earth indefinitely.