Answer: Product of masses.
- A Sum of masses
- B Product of masses
- C Difference of masses
- D Square root of masses
Correct answer: B. Product of masses
Explanation: F = Gm<sub>1</sub>m<sub>2</sub>/r<sup>2.</sup> Force is proportional to product of masses m<sub>1</sub> x m<sub>2</sub>.
g is maximum at Earth's surface; going up, it falls off as 1/r² (inverse-square); going down, it falls off linearly with depth (since only the mass enclosed within radius r contributes), reaching zero at the centre.
Concept context
Universal gravitation, orbital mechanics, gravitational potential, and escape velocity.