According to Newton's Law of Gravity, what is the magnitude of the net gravitational force exerted on the Sun by a planet of mass m orbiting at a distance r with gravitational constant G?

• A. G * m * M / r^2, where M is the mass of the Sun
• B. G * m * M / r, where M is the mass of the Sun
• C. G * M / r^2, where M is the mass of the Sun
• D. G * m / r^2, where M is the mass of the Sun

Answer: (A)

Verified step by step guidance

1. Start by recalling Newton's Law of Universal Gravitation, which states that the gravitational force between two masses is given by the formula: F = (G * m1 * m2) / r^2, where G is the gravitational constant, m1 and m2 are the masses, and r is the distance between the centers of the two masses.
2. Identify the two masses involved in this problem: the mass of the Sun (M) and the mass of the planet (m).
3. Recognize that the distance r is the separation between the center of the Sun and the center of the planet.
4. Substitute the known values into the formula: F = (G * m * M) / r^2. This represents the magnitude of the gravitational force exerted by the planet on the Sun.
5. Understand that the gravitational force is mutual, meaning the Sun exerts an equal and opposite force on the planet, according to Newton's Third Law of Motion.