What statement best describes Newton's Law of Universal Gravitation?

• A. A force is proportional to the distance between masses.
• B. Gravity only acts at short range.
• C. Gravitational force is constant regardless of distance.
• D. Every mass attracts every other mass by a force proportional to the product of their masses and inversely to the square of the distance between them.

Answer: (D)

Gravity is a long-range force that depends on both masses and on how far apart they are, following an inverse-square rule. The statement that best captures this says that every pair of masses attracts each other with a force proportional to the product of their masses and inversely proportional to the square of the distance between them, with the constant of proportionality G. In equation form, F = G m1 m2 / r^2. This means bigger masses pull harder, and increasing the distance makes the pull fall off quickly—doubling the separation weakens the force by a factor of four. This universal interaction applies to any two masses, no matter how far apart they are.

The other ideas don’t fit because gravity does not grow with distance, nor is it limited to short ranges. A statement claiming force is proportional to distance is incorrect; gravity is inversely proportional to the distance squared, not directly proportional. Saying gravity is constant regardless of distance ignores the r^2 in the denominator, and claiming gravity acts only at short range contradicts the universal, long-range nature of the force.