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 = Gm1m2/r2. Force is proportional to product of masses m1 x m2.
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.