Answer: Long-range, always attractive.
- A Contact force
- B Short-range force
- C Long-range, always attractive
- D Long-range, attractive or repulsive
Correct answer: C. Long-range, always attractive
Explanation: Gravity acts over infinite range and is always attractive (unlike electromagnetic force which can be attractive or repulsive).
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.